Osprey battle orders 009 japanese army in world war ii, conquest of the pacific 1941 1942

Unit designatton practicer *Task organization for combat *The 1940 standard 0 infanuy division The square Infantry division * Independent brigades *Tank regimens Tactics Enntapmertt an

Battle Ord

I

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Acknowledgements

Special thanks are due ro Akin Takizam, William Howard and Shigeyuki Mimno

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Unit designatton practicer *Task organization for combat *The 1940 standard 0 infanuy division

The square Infantry division * Independent brigades *Tank regimens

Tactics

Enntapmertt and en~irclement Tank and artillery coordination

Small-unit tactics in the Philippines

Weapons and equipment Platoon weapons CornpamyEbamlion weapons Regimental weapons * Arrillery Tanks

Command, control, communications, and intelligence

Command Commwnicationa Intelligence

Introduction

1%'~ Ijy the gracc of Hravcn, Emperor nf Japan, reatcd on the Throne of

a line r~nbroLen fnr age5 eternal, enjoin upon !.c Our loyal and brave

subject5 of Ours shall pursue heir rcspcctivc d u t i ~ s;hc cntirc nation with

n united will rhall mobilize thcir total stret~ath ro that nothing will

m i s o i l r ~ in the attainment of Our war aims

Japan (Sipport) viewed IVorld IVar I[, ~rhich it called the Grcntcr Fast .4$a War (Dni 7 0 0 Sr~r~srl Srrlkrr~lr) as a seric5 ot intcrrelntecl ttTars It had occupied

part$ of Sofill China in 1931, a n d the w a r in China [ S l r i r ~ r l IEli~rr) hegan in earnest in 1837 in which Japan continued its crc~ping expansion Conflict

wit11 the S(1~tc.t Uniorl Iiad occurred on the Siherian harder in 19.38-39 in

h l a n t l ~ u r i a , or hlanchuko, whcrc a pupl>et state had hecn cstablilled by Japan

in 1932 In July 19.11 jnpnn occupied French Indochina in Southeast Asia

The Pacific 1% ( X ~ i l ~ ~ i l o S i ~ ~ ~ q o l began at 02.15, Dcccmt~er 8 , 2601 Tokyo ~ i m e ' ( " X-Day") \Y hen thc 2rl Southern E x p c d i t i u n a ~ I:lc-ct bornbardeci British forces

a t Kota Hliaru, ma lay;^ Fnllowcd t ~ y nmpllfbious landings The first bomb

dctnnnicd on Ford Island, Pmrf Harbor Flarvaii at 113.45 Tokyo ~irnr' The

urnc day, Japanese land, sen, and air forces alw struck the northern Pliilippine5, e l s e t r v l ~ ~ r c i n MaIn~n, Sillgapr>re, Ilong Kong, Guam, IVa'aRe, and r>tlirr I'atific island<

Thc goal of the Greater Eart :t?ia War war tn drivc the armed forces of the

W e ~ l r r n colonial powcrP from the re%st~rce-rich Ketherlnnds East lndirs (NEI),

t hc US-cont rnllerl Philippinc~, the Commonwealth porrcqrions in thc

South Pacific, ant1 Rritish-controlled Malaya and Burma :\ military operation

of ~ r e a t niagni tudc ~ z v u l d inflict a decisive defeat resulting irz the IVestcrn natinns suing h ~ r peace, a n d allowing Japan to establish the Greater Iiart Aria

Co-pmrl>cri t) S~,hcre (llni Trlrf Kw)ri-Kr?;l O~tensil,ly this M'JC aimed a t the mutual hcl-tcfit 2nd liheratlnt~ of all :\rians; in reality it5 poaI was Sippon's

enrichment Japan would ctlloniz~ and maintain total contmf over k i s t Asia

exploiting itr resources and crtnblishing a r e n ~ r i p zonc tn pro:cct it from tllc threat of \2'estern influcncc

Thi5 hook covers tl~c period from the beginning of thc G - 3 r e r Eii5t Asia

War in December 1931 to t11c war's turning point in lune "v Rattle of

Miriway It covers o~~crationr in the Philippines, YE], an.' b r '" '~lcitic, hut not nhose in China or Southcart Asia Future planncd v-'. - -i - :he Battle Clrdcr series w ~ l l cover Japancsc operation5 in S o u t h t ; ~ ' ' - - .:1-45, the

Y > hM zone

8 % mdsr~red for m m p l e 03 t 5 z a p p % c d to 0345 Dates m r r d the l n r e m a r r m Z r -01c to

the e z t Japan hnd adoprcd the Wertem rolar, ar Gr@gor~am, rakndar ~n 1873 to e x : c dJ:tJ

being admnccd t h m re s>x w e b m brmg d v md months lnto common a l t g m - n I &r

bean l a thc W s r c r n year of bba BC (the laundlng of theYamaro State,prcdwcsr : -7 ,- " 9 4 t

South Pacific a n d New Gz~inca lrnm 1942 l o 1 W-!, the 19.1445 defensc of tllu Philippine% and Central a n d \Vest Pacific npcrations from 19-13 to 1945 The genesis of t h e Imperial Japanese Army

Prior to Iiic 18711s, japan wa? a trucli~l rclclcty n~rnl)ri.rlng over 1211) rcnil- autonomuus domains ruled by warlortl\ crC tlir \nr~irrrtri clar% 'Slicy onycd ltrcir

a l I c ~ i a n c c ta tllc S ~ I O ~ ~ ~ I I I , t h e tnili tar? ntler: t h e Ern peror had hccn a mcrc

figurchcad sincc t h c Intc- 1 Zth tentury Ibr centlrrivh Fiippnrl cuI\tccl in the form ot a Wcstcrn medieval state, and was subject t o almost continltrmr civil war dnd rebellion

Japan w a s opened to \llestern influence in t h e rcakc of US Commodore Matt hew Parry's 1853 visit I t s esptwre to n ~ c ~ d e r n tcchnnlogicr, c~pcciall!

with regard t o wnpnn5, rc5i11ted in a %cric% u f tradc trcatier wilh thc US, Britain, Russia, France, and I-lotland h pnpular Jogan of t h e time ~ v a ~ , "l.:artern

ethics, Western science,"' hut others such a5 "llcrerc the Ernpcror, c s l ~ c l the barbarians" demonstrated the tcnrionq t h a t r i ~ n m c r e d t ~ c n e a l h tlie rurfacc

~ \ l t h o u ~ h Japan had been introduced to firearms in the mid- 1 6th century, its r E i c ~ ~ ~ ~ l r r i i ~ t r ~ arm ics rt i l l largely compriwd rrvclrd-, spear-, anrl bow-and-arrn~v- armed ~trrrrrrrni hacked by pea3anl l e ~ i c 5 that owed allegiance t n their partici~lar clan Ry IHSIF rnurketx a n d cantrons had come Into wider use I n 1861 rlflc

unit3 tSlrr>tiri) rvcre formed with a mix of traditional and modcrn \\.capot1?, and the lirst distinctions were made bctwccn i n f a n t p , cavalry, and artillery branches In 1866 the modern Sllutlri, manned with nationalist strr~~rlnli !tvIlo sought t h e restoration of the Emperor, d e f e a t ~ d the s / r t ~ f r i t t i r l ~ army in battle The Emperor war restored in 1868 Japan also seized control of Okinatva and

the Ry~k!.u Islands in 1867

The .l.lr*iji (Enlightened Rule) Era c 1868-1 81 2 1 saw ilrajor cffortx to cstablirh

Japan's rightful, place in the world and huild a modern society N o t onIy wcrc government and mciev considerably It'estcrnizcd and modern indurtrializat ion efforts begun, but military ad\Ssor? wetc alco cngagcd, nrostlv from France Z~ut with others from Germany, Rritnin, and Arncrlcn Officer train in^ rcIiools wcrc etablished, althougt~ trainina was restricted to company level The Imperial Guards rKu~ive) were ertnhlishrd in 1871 tram t h e exi\ting Imperial Bodyguard ft;o~lriripi~i) n t ~ d armed arrd trained along 1frstt.m lines In Fel~ruarv IS;:! a rcparatc army and navy !\-ere formally rstahl~shed The army wa5 called the

Silrnrtf~rt~ or Kukr~,~iirr-lnpan'c or the Nation'$ a r m y

Conscription was imtituteti in I X J.{, with rererw senlice requlred after three years' active duty, Japan strovc to establish a moriern national arm! and followed the hert European nlndcl\, adapting tlicm to i t s own reqriircmonts In the wnkc of Prusria'r defeat uf France it1 l 8 i 0 , Japan adopted German general 5taft arld organizational principals, implcmmtinl: its own <;enera! 5taH in

1879 The General Staff College rr\'as npened in 18X3 The Llilitav l'olice

Ket11p~it17il rvas ra~sed In 1 X 8 1 and a n Intendance Corps (acimini\tratiot~ and

services) in 1888

Tactically, Japan retaincd the concept of inasscd troop format ions, nmch

ar per the nld hand-to-hand battles rather t h a n t h e dispersed f o r m n t ~ o n s adopted in Europe l'he day of the wt711iriri rvhn liired on government stipends,

was cornina tn an cnd though Thev were offered a final lump rum, which

was made compulsory in 18Yh: tI-~o~c who rejected i t were forbidder1 to rwar

~word5

rn 3885 the Emperor was given two means of directing militan' authorit?:

pprlrrrei and pr~lsei: it war a move that rcould have a major impact on ho\zUJapan madc war in the fittlire I;rr~rrr,i covered command, strategy, training, troop deploynrent, and dircipline l'lr~s was executed through thc ;lrrny Chief of Staff, and impacted on foreign affairs, h).-passing t h e Prime blinistcr and Cabinet

Grrrlrei dictated military adminirtratirm, the Army's size, arrnamctlt, wpptics,

and conscriptinn, ant? r z w executed through tlie War Mlnirtcr

In August 1894 Japan declard war on China to achieve its goal of gaining control of Korca, a longtime enemy The stage had been set for such a move long before this in 1881, when Japan's security needs were defined to include the possihitity of territoriat expansion In October 1894 the Japanese Army entered

Manchuria in pursuit of a battered Chinese army driven from Korea Japan" first modem nvar, and its first overseas expedition in centuries, won the Empire Korea,

Formesa (Taiwan), the Pecadores Islands, and Liaotung Peninsula In less than two decades Japan had progressed from a collection of clan armies led by feudal warlords wearing lacquerd bamboo armor and kimonos and armed with swords and spears, to a unified, sixdivision, combined-arms force led by professional

officers and armed with bolt-action repeating rifles and breech-loading artillery The Chinese army defeated In the Sino-Japanese War was admittedly a poorly armed and led rabble, but Japan would prove her military prowess again soon

after Six more combined-arms divisions were authorized in 1896

P l ~ e construction of the Trans-Siberia Railroad increased Japanese Fears of

Russian expansion in Siberia In 1900 t h e Roxer Rebellion broke out in China, and Japan provided almost a third of the troops for the eight-nation Peking: relief expedition As a result, Japan gained the right to station troops in China's internationaf settlementr, Peking and Tinsein, and the China Garrison Army was instituted The 1904-05 Russo-Japanese War astounded the world with

Japan soundly defeating Russia on both land and sea in a conflict over control

of Manchuria, Although the Russians dld not posses the most professional of armies, and the Japanese had their own shortcomings, the war saw t h e defeat

of a lonpestabllshed European power by a n Oriental armv still emerging from the medieval era

In the Russo-Japanese War, the Japanese employed corps-level commands,

designated "armies." It began the war with 13 divisions and ended with 17 Six tnore divisions were raised between 1905 and 1908 working toward the goal of 25 standing uobi) and 25 smaller reserve [Kohi) divisions to s e m as replacements for the standing divisions At the same time the N a w adopted

i t s "eight-eight fleet" plan, comprising eight battleships and eight cruisers Bp

1907 there were 19 active divisions 'The war left Japan in control of Russia's

Guandong (Kwantun~) Peninsula leased territory2, the Russian-built South Manchuria Railroad, and in a strong enough position to annex Korea outright

in 1910 The Manchuria Garrison Force was established to secure the newly acquired temtory Japan was now in a perfect position to expand further Into China in 1931

171e victory over Russia achieved far more than merely gaining territory

and economic advantaw for Japan; it gained the world's grudging respect It also

gave Japan a new self-confidence, increased its industrial capabilities, and placed

the armed forces in a position of esteem All of these factors tuould contribute

tn the Empire's increasing aspirations in acquiring territory and resources

The Tnirlio (Great Rigllteousnessl Era began with the accession of Emperor Yoshihito in 1912 With the armed forces still basking In the glories of the Russo-Japanese War, this era would soon see further expansion of the Army to garrison its territorial gains as well as the acquisition of new territories It would

end, however, with a reduction of its divisions by one fifth,

With the opening shots of World \Var I in 1914 Japan promptly took over the German colony in Tsingtao (Qingdao), China and the Kaiser3 possessions In the Central Pacific, the Mariana, Carollne, and Marshail Islands, which would

become springboards for Japan's future Pacific conquests During World War I an

additional two divisions were raised specifically to garrison Korea as the Chosen (Korea) Armv, and a brigade was established on Formosa In 191 9 the Manchuria Garrison Force was redesignated the Kwantung Army Japan hegan occupying

I Kwanwng h a small pcn~nsula cn whlch Pon M u r k s ~ u a r d , lurtlng mio therenwr ka beween K o m a T m m

Chrna Whle bearing the der~gmuorr ofth~s small rma,rhe K m n t u q Ammy was c*rcnrually m p n n M e for all ol Manchuria

f hc Koh[,qrrn, or na tional arm!; was rederignated S7oi S i p p t ~ r r 7i.iknkrr

Kibu~un (or 5imply Ko,q\~rt) the Itnperiat Japanese .lrrny (FJ.4 I 'I'his, along

w i t h changing IegirIatic~n, h a d t\.irle-ranging effects o n tlic prychological and legal authnrity of ihr .-\rrny, and its mle I\-tratever it did now, it did It fnr the F.rnpernr

TIlc acccrrion of Empernr I-lirohitc) in 1926 sarc thc dnw11 of rhc 9 ~ \ \ 7 < r

enlightened Peace! Era and tvould rocln see rcncwcd efforts to d o ~ n i n a t ~ CIhina [$?tween 1926 and 1939 well over a dozen new n ~ o d e l r of individual and

in fan try crew-srrt'cd tvcapcsns, from p i r t d s through machine R1lnS to mortars

and infantry guns, wcre adopted Scr\ artillerv, antiaircraft guns, and t a n k were also fielded, hut rccrc inferior tu crmternpurar?' IYcstcrn rlcsignr end too few Motfern antitank rvcaponr wcrr c3~cntially n o n - e s ~ s t e n t

Thc 18305 saw Japan pursuing an aggressive policy in China initiating a

scriw of " i n c i d c n t ~ , " cumulating in t h e I'I:J7 CllIna Inciclcrlt (.A Japnnrsc

"incident" could be a n y political-militan cvcnt ranging frnni n nlinor

s k i r r n i d ~ to large-scalc conflict, hut short nf dcclarcd war.) I'hc Zrrny incited much of this ol itr own accord w e n i ~ n o r i t ~ y : ordcrr to cease CSfficcrr of t h e

K w a n t u t ~ g -\rlny initiated a plot to incite Chinew force3 hy d v n a ~ n i t i n ~

~ c c t i n n 5 o f tlic Snuth Slanchrlria Rallrond Using thir ar an excure, t h e

J s p a n e w rrcc~xpicrl \Iukden IThiie prtitili~ing t h e I,eajiuc af Natfanr it wnuld

~vithdrarv, anritlicr incident was initiatccl resulting in the invasion of t h e xouttlcrn Mi~nchuria provinccr still in Chincrc harlds, e n d i n g in the rapid

dcfuat of thc clcfentirrs In carry-10.42 t h e Firrt \hanghni Incident w a s

brnvght about, a n d the Japanese occupicrl t h e city tci "protect" Jnpariese

nationals Further attackr wcrc latinchcd, more n l Xlancliuria war occupied,

a n d tllc puppet rtatc of Mnnchukuo was e~tablishetl Large n u m h c n nf Cliine.;~ ~ u c r r i l l a s continued tcl fight 111 k l a n c h u t ~ a , although thc Japarlese

"anti-handit" campaign5 Ilad been mostly successftsl hy late-1934 Japan was condcmncd hy the League of Nations In carly-1932 for its aggrersion in China which i t ignored This rumlted in Japan tendering its two-year

notification of its rvithdrawal from the League, which war FinaIized in 1935

On [ h e hcels of t h e condcnlnntion, Japan occupied more of Inner Mongolia, incorporating it i n t o M a n d i u k u o The Japanere position in China wa$ now

m strong t h a t it forced the withdrarval of Chinere forces from Peking and Tienrin :I process of divisional t r i a n g u l a r ~ r a t ~ o n began in 1936, wit11 thc

e l ~ r n ~ n a t i o n of a brigade hendquartcrr a n d the withdrawal of an infantry regiment Thi5 allowcd the f o r n ~ a t i o n af additional rlivisions The Kwantung

Army cnntinued <mall-~cnlc operation5 throughout northern China into

1937 C3n July 7 , 1937 t h e Japanese engineered the h1arc.o Polo Bridge lncideilt outsidc of Peking, leading to all-out war with China known as thc China fncidcnt Thiq was seen as a chance to neutraEize thc Chincsc as a threat to the Japanese southern flank It would t h e n aIlowo lapan t u face the

"real" enemy, t h e Soviets threatening Manchuria 7 h c policy overall was

knorvn as the "Strike North."

Ores 180,000 Japancsc troops died in China a n d over 41)0,000 werv taLcn sick o r ~.uuntlett unJy n ferv ycan prior to tllc hcginning of the Pacific it'dr,

\2'i th 23 divisions fighting the Chincsc, ninr were prepared to fight t h c Sovicts

1:ighrin~ broke out on t h e Siberiatr border with the USSR in 1938 a n d 1939 reruIting in ernharrarsing japar~csc dcfeats in t h e long arvaited confrontation Frenrli Indochina was nlrcupieti in 1941 through "agreement" with t h e

colonial govemmcnt aftcr lhc fall of France I\ mil lion tmops werc lnobilized during 10-10 Tllc feasibility nf invarling tlic south n*a< stuciied and what wcrc

termed "Strike South" conlnlnnd excrrises were conducted 'Thrt>ugIr all this

J a p a n signiticantly incrca~cd its divisions, air service, and other unit\ tn bring

t h e Ilh t o 51 divisions 59 brigade cquivalents, and 151 air hattaliilns on Ihc cve of t h e Greater I l a ~ t Asin \I7a'ilr ((7t these d i v i ~ i o n s nine had hecn orgnnizcd in

19-10 and (me ~n 1941

I Table I : disposition of Imperial japarwse Army forces December 1,194 1

I (exclusive of Southern Opefitions Forces)

1st Air Group (nine alr battalions)

4th Division (IGHQ Reserve)

Manchuria Air Brigade (21 air bamlions)

2dAir Group (35 air battalions)

North China

I China Expeditionary Army

North C h ~ n a Area Army

27th 35th I 10th divisions

I s t 7th, 8th lMBs

(coniinued on page 101

Formosa Army (combat units detached to Southern Army]

f he outbreak of t h e Pacific War, 194 I

A detailed expore of Japan's reasons for going to rvar with America, Great

~ritain', and the N~tlierlandr i s beyond the scope of this book In

brief, the League of Nations condemned Japan's increasingly brutaI, but bogged down, war of aggression in China Economic embargo$ were

implemented hy the Pacific colonial powers as a resuIt, especially forbidding the exportation of oil and other rerources to Japan, resources it did not

posses% Verging on a colIapre of i t s war effort and national economy,

Japan war forced to secure a vast region of Southeast Asia and the South Pacific in order to control the natural tesources it required for its survival At the same time it wou!d establish a security zone in which to expioit and

transport these resources to the Home Islands and between the areas

it controlled Japan realized an extended war was possible It was essential that the "Southern Resource Area" be secured and exploited as quickly

as possible in order to wage a protracted war She possessed liquid fuel stockpiles adequate for less than two years of war A National Defense Zone would be established through Burma down though the NEI (Sumafra, Java, Timor), Western New Guinea, the Caroline and Marshall tslands Uapanese Mandated Territory), anchored on the remote Wake Island in the north

1 Jnpm made Ilrdc dlnrndnn b@wem Bdcrln,Aurmllhmd New Zealad and seldom m 7?n! BnA Cwnmorrweakh

In lapa& e p s B n e ~ n was a colennal power and rhe Commonwikh members mere cobm d a V m - m - Iwn slmplr

The Southern Army's pre-Invasion depl~ymens December 194 1 Only units

d g n e d to Solnhem Amy are indicated

japanese both Army and

Navy, lead the vicrory march

through Hong Kong after i t s fall

on December 27 194 1

Enstcrn Scrv Guinca lvnuld be recured as !7,ell a3 the C;ilhert and Solomon lrlanils as a huffvr mne The cnnili~esed Southeast Asia arcas of the NET, Rritisli Rnrnen, and tlic I'hilippinrs zz.ould he defended by t h e IJA, a n d naval arid air force5 of t h e C n n ~ l > i n e d Fleet ~ v a u l d rngagc an)' attacking flcch

in rchat war c n v i r ~ o n e d as a Jutland-Iikc decisive engagement Thc !IN n7as

alro respot~sililc f o r 1I1e dcfenre of mo<t of Sew Liuinea, t h e SoIomons,

Carolineq, Mulanhalk, and Gilberts I t wa? hoped that t h c Allies, after rcpcatcd

h l ~ m i l i a t i n ~ defeats, wouIil sue for peace and leave the Ernpirc uf t h c Sttn to itself within its Greater Kart ; \ ~ i a Co-prctrperity Sphere

With no dipiomatic solution believed obtainable, Japan mmmittcrl itsclf to war

~vilttli the Ilkstern colonial powers on Sovt.mbcr 5, 1'441 Initial prcpardtions for

" Z Operation" had l o n ~ heetl unclenvay; the Pcarl Harbor acnck had k e n propored in January 1941 and 11A zlnits had b c p n m i n i n g in Aug~st, but it was

in Ihc car!? days ol Novcmbcr that the linal ordcrs were issucti Intclligcncc

coltcction had t ~ e r n undewav for ycars The objectives wcre the dc5truction of thc major US and C o n ~ m o n ~ v e a l t h flect units and thc seizurc of the Philippines, NEI, Malapa, Thailand, Southcnl Burma, Hung K o n ~ Singapr)re and Cum ti~on~vealth

yorser~io~lr in the South Pacific l'hc A~nrrican t e r r i t o ~ of Guai~i, within the Japanere Malldated Territory, war alrn a kc? objective

Since the mid-1 970s thc IJA had allotted three dlvirton~ to scizc I.uzan and

onc for Gliam America though was not considered thc main enemy That di~tinction fpTI to the USSR Bogged down in a ce~mingly endlers war in China, Japan hoped to secure thc Southern I<c\oture Zone withill five monthr and then rodeploy half of the forces to bianchuria They would he prepared by the

5pring of 1043 for t h c USSK to cnllapre i ~ n d e r the Iierrnan invasion or pull mo%t

of it5 20 diuisinnr out of Siberia r o face the Germanr The fact that France and tlic Xcthttrlandr hat1 heen occupied hy C;crnma nv, and that Rr~tain looked likely tc3 follow Toon, t purred t h e J a p a n e ~ e on America war vietzled as weak hecause

its lndir-idualirrn and lit>eralism ~ \ ~ u l d prevent ir from fighting a lengthy war

!\ugust 1941 ,lapan had tcmpnrarily abandoned t h e idea of attacking the

LrSCR and began tu fc~c~rlr attcntion to t h e "Strike South" concept

Tlic order arsignirtg forces to the Smthern Army was issued nn Kovcmber 6

and objectives as<igned to specific unitr on the 20th The Gnnrhincd Fleet

issued itr fint order5 and assignments o n Novernher 5 and "X-Day," thc start

of ho\tilitier, was riesignatetl a? 13ccemher 8.111s %\+as fixed on Dcccnlber 2, as tlle I'earl Harhor Task Force was en route to its target, to commence at approximately

05.30 nrl Uccembrr X (li~kyo Titncr A Iiigh depw of cooperation wo~ild be rcili~irccl I ~ t w e e r i thc []A and inlpcrial Japanmu N ~ F 4 IlNi TIC Arnly-Nay Central \greenlent was sign~d on Not+embcr 1 0 by thc commanders-inthief of

t h c Southern , \ m y and Combined f.'lcct

Combat mission

'The Southern Army (nftcn incc~rrectly ider~tified as "Southern Area Army")

was crtablished o n Nnvcmhcr h, 1941 t o control alE IJA m i l s assigned t o thc

S(ntt11crn Operations The cntnmand was Iieadrlnartered in Saigon, Frcnch

lndocliina under Gen Cnunt l'crallchi Misaichi (alro lictrd as Juichil Thc plan was certainly ambitious Thc schzurc of all of Southeast ;i%ia, the NEI, t h r I'hilippines, a n d rcgirms of t h c South Pacific ~ ~ o u l d bc a c c o m p l i ~ h c d Ilv o n l y

1 1 infantry divisions, four hrigadc-ri7c force%, and 70(3 11:2 aircraft 400,OOfl troops in total This area stretched ncrms five time rnner aiid tvas larger t h a n

t h e Continental United Stater lapan rvas countiny: on surpriw, and tlir reFativel~ unprepared a n d rveak force5 ficldcd hp thc colonial powcrs I t s own resource5 ~ v o u l d Ile stretcheri t c ~ t h e limit with tranrpr)rt q t ~ i l ~ p i n g ~ ~ u l l i n g

douhlc duty tn tilove troops She unit5 In~tiaIly ar.rignccl tn thc Philippines,

a n d t h e n wn7e ar occi~patinn troops or conduct I ~ r r t h e r conrhai opcrationr

Almost half of t h e lJ.4'~ 1.500 combat aircraft c could be required and the Iwst air units werc taken from o t h e r cornmaridr for a\rianrncnt t o thc 3d a n d

5th ,Air Groupr

In December 1941 Japan possesred 51 divisions s ~ t p p l e m r n t e d t>y 59 brigade-equhalentf, but many of thew were nr~n-deployable Iwir~g garrifon and

line-of-communications ~ c c u r i h forces in China 'I'wen ty-cighl div~rlclnr rvcrc i l l

China with most c i ~ g a g d in combat or occupation duty Another 13 were in Manchuria and Korea t a protect the Empire's northern frontier with thc LrSSR

Two of the five divisions rcmaininy: in thc Home Islands were nwlu raked and

partly trained Tirc cxccptinns were thc 7d conimitted to the Soutl~crn Clperationr, the 4th as the IGHQ Resen~c, and the 7th tied tdo~cn protecting narther~i Japan

from the USSR There wew alro 10 brigades in Japan and nine d e p t divirionr training replacements

The 1 1 clivisionr and othcr forces asri~ncd to thc Southcrn Arm! ~t-ere dm~vn frorn a number of sourcc~ and scattered throughout the Empire when the Sol~thern Army was nrganizcd Fivc division^ caint from the I l o ~ n e Islands, five from China, a n d nne from Formosa

The 1-lth .Army t v a s designated the Philippines Attack Force with its headquarters and army troops, 4stt1 Di\+ision, and ci5rll Brigade o n Formosa r'hilc

the 16th Dn-isic~n was on Arnnrni Shima In the R I I ~ ~ I Z ~ Islands Other sn~all cleincnts were in tlie I'alauc and I'cscadorcs Thc 5th \ir C;rotip (20 aa battalions, from Mai~churia izuas deployed to Forrno5a for I hc PliiIippines operation with two fighter, hvo light-hc~rntrer, and one heai?.-bon~her rrgirncnts plus a reconnaiswnce unit It was crtin~ated the operation would reqlrirc spprosimntely 50 da!.5 At the

end c ~ f this phaw pit? trF 14th ;\rrlly forces wnr~ld hc rcas5ipncd to cnmplctc thc more critical NEI opcration -The 4th Division, the IGHQ Re<rn.c in lapan, tcould

he committed to the I'hilippincs later

The Rurrna .Attack Force, whicli r\.ould Rnt rccurr Thailand, rrar h t ~ i l t around t h e 15th Army in tndnchii~a with the headquarnrs and a detachtncnt

of the 55th D i v i s i ~ n in the south along tzqith the Guard$ Division (temporarily detached from 35th A r r n ~ l The 55th Division (lcgq clcmc!itsl was In thp north

and the f n l l n ~ , - o n 33d [liririon MI in <:en tml I:hina Hurma nperetions tvould

suhrcquen tly be reinforced Fmm units relearcd from other areal; Its cclmplet inn

w a s forecast to be within 100 da!'s

The Jcl~hern Operations plan

eactivated i raining, whi -

taised at N;

Bng From

am in late- l

agga law there ir ser

1 942 and m

65th Brigade This b r p b e was raised at Hiroshima.Japan in ear+-1941 from the 65th Independent Inbntry Group

lr w ~ s ~p_~lr M 5mtz and &m hdd an Luran in December 194 I, 2t hughr them and remained

on the Wand until December 1942 when one regiment and the HQ were sent to Rabaul and the

other regimenu elsewhere.The brigade was dissolved in late-1943 aker b unlts were absorbed lnto

arhen Commander: HajGen Naka d k i a Guards Division Activated in 1867 In Tokyo ir grew in size wer the years lu 2d Guards Brigade and two regiments

( k n o t Shidan) were sent to China in I940 to experience their fim combat In 194 1 h e l st Guards Bripde and its

units were detached and reorganized as the Guards Mixed Brigade.The I d Brlgade units in China

became the new Guards Division with augmenration by the 5th Guards Infantry In mid-1941 the

division went to lndochina then Thailand and Malaya In March 1942 is was deoloyed to Sumatra and

in June 1943 was -designated the 2d Guards Division when the M s Brigade ir became the 1st Guards Divislon Commander: LcGen Muto A k i n

336 Division Organized in March 1939 at Sendai.japan and sent to China the folrowFng month where i t compMedl 1

mining It fought in Cenval China until departing for Thailand in December 194 I By Man was fighting in Burma.where it remained Commander: LtGen Sakuni Shorn

55th Division Amivated in August 1940 a t Zentsuji.Japan.The Division (less elements) arrived in Indochl,,, ,,

December 1941 and wem lnto Burma Its 55th Idantry Group and 1 4 t h Infan- formed the South Seas Detachmen& which secured Guam and Rabaul.Tumed Lack from Port Moresby durlng the Battee

of the Coral Sea it was later landed at Bun& and was demroyed It was rebuilt and rejoined the divis~on In Burma in 1943 where it ended the war Commander: S e n Takeuehi Yiroshl

2d Division Raised In 1870.8 fought in the Sino-japanese and Russo-Japanese wars It deployed to Manchuria In

the 1930s and was soon engaged in North China: it then fought the Soviets in Manchuria in 1939 It returned to japan In 1940, and again departed in January 1942 w arrive on jaw in March where it helped complete the operation I t rms sent to Rabaul, later destroyed on Guadaleanal, rebullr at

Rabaul and spent the r e s t of rhe war in Sowhast Asia Commander: LtGen Marupma Masao

th Division C r 1873, it xemalned a square division at the beginning of the war and was partly

n s well as amphibious trained It fought in the Sino-Japanese and Russo-Japanese wan Ir rteptoyea to China in 1937, fighting there until September 1940 when it went ta Indochina It onducted brief operations in China and then mwed to Hainan Island off South China betore landing

~Thailand From late-1942 It =cupled and garrisoned various small islands in the NEl.The 4 1 st

nfanrry was detached and bught on Panay and Mindanao in the Philippines and then on New Guinea.where it was pa* destroyed I t was reassigned ro the 30th Division Commander: LtGen MatsuiTakum

18th Division Activated in 1905 at Kurume Japan it was deactimted In 1925 as part of the I]& reduction Ir was

In September 1937 as a square division It moved co China in November to complete its

:re it saw much a d o n tmtil late-1 94 I It landed in Malap in December and subsequently ought In Bunna where it remained Its 35th infantry Brigade and 124th Infantry were demched and

ewed on Borneo, then Mindanao and finally 11 where it was largely deswoyd It ws

ebuilt onTruk and sent to Burma where it v ted to the 3 1st Division Commander: LrCen

4mguchi Renyk

5 to Java, Sumatm,Tirn ?r NEI Islands It assembled on baul, Much of the divis ,t on Guadalcanal I t m s rebunt a t

-

n I r3f and fought in Cnlna urn11 NOVemwr I 74 I lt banded on Lun lary 1942 and concluded the operation Ic m m e d to Japan in June where it remained until September 1343 when

it was sent to garrison Sumata Some detached battalions fought In 6urrn~'l"he division mwed t o Thailand in April 1945 Commander: LzCen Kitano Kenzo

Tadayushi

,e wars It d

on in Febru

D o c t r i n e

SNLF rroops shine flashlighu on an

Amer~can flag to lnd~cate KO aircraft

that they have captured Agafia,

Guam,Thrs drawing from rhe

50th Annivermry booklet shows the

rroops wearing rising sun armbands,

a detail w h ~ c h has not been verified

The Japanese forces were fairly well

equipped with light bridging and

brldge-repalr rnoteriebTfiey

recogn~ted the necessity of

malntamng rhe speed of offensive

difficult

Thc u:2 rlevelnpcd its tactical doctrine over the 40-year period prior to the

outhreak of \\.orld \.Va:ar 11 L y studying and adopting ay~ectr of Western armies that hest rr~ited its necdr S o one nmiy \cn+ed a t a pure mndel though, and arpects of

doctrine would he modified to t i t their traditional concepts Japanesc combat

esperience during the 40-?car period in question crTas more di~~erst? than often thought Thcv fought Chincsc force< of vaning quality, rangin): frnm warlord-led

gangs, through guerrirlas, to prokssionally led, 1%-ell-organized forces of sub5tantial size and qualitv They also f o u ~ h t well-trained, skill fir lly led, and better-equipped SorSet forcer The IT:! also gaincd vast experience of fighting in different terrain, climate, and operational contfitions Thcxe included the barren plams of SiF~cria against amlored and mechanized forcer: the forerts, plain?, rugged hills and mntttltain~ of northern and central China; and in cities and r~ilIilges T h e climate extrcnier ranged frnm biting cold to derert heat, from torrential rain to dust stonm hIany i)f the area$ fought ~n lacked detpelopcd road sFtems and railrmdr

Contrary tn popular early-war perception, the japaneqe were not trained fox jungle n'arfare Iinr wcre they "natural" jungle fighters Japan had no place in

~chich tn conduct such training and most troops were fanners, fishernlatl, and

urban worken Mort units that fought in the kciffc and Southeast Asia dcploved dirrctl! From the chilly fall climatcs of China, Slanchuria, or Japan What their pre\.ious espcrience d ~ d pmvide w a ~ 'the ability to operate in varied terrain and

climate condition% against enemy forces of cqually varied q11aliQ' and mpidlilitier

'I'lieir orvn sell-inff lcted aurtere field conditions were a major factor and prepared thvrn wcl! With srlch experience behind them thelapancsc tvcre able to study the condition5 of the expcctcrl areas of operation and adapt their taalcs, equipn~ent IeveFr, tark organization, and logi5tics accordingly Ihey were not always

SI~~CCSFF~II in this, for example on Net\ Guinea, \vlrcrc they ~ c n t l y t~nderertjmated the conditions Their equipment tvas already comparatively light and much of it

rIesi~ned to t ~ e man- or animaI-packed TI~cir logistics tail was less burdenromp than any ihrcqtern amiy's, although this meitnt it rvas fragile and easily disrupted

Offensive operations japnnc~c tactical doctrine foc~lseti on attack, surpriqe, rapid movement, comm-

arlderr aperating wcll for%\*arrl, and rclati~ely rimple plan? Offensive actions were the rlom In thc 1928 edition of Rmri Konw I Prir~cipie~ nf Smtc,cic f i m n r r ~ ~ l r f i , thc

wq2.nrdr defenre, rctreat, and stirrcnder were c x p ~ ~ n g c d , as they wcrc considered

detrimental to morale and the militaw ~piri t - f i ~ c lapanese found rlefenslve

act ions to Ix ial~horretlt I I s lapancrr nFlccr werc mnfmn ted wit11 an unexpected,

tlnurual, or cornplimtetf rihlat~on in lunli., h c rvould find a way to attack, :$II

attack wt~uld be executed at u n m p a c d timcs and place3, long unanticipated

routes and often with force ratio5 that ~ Z ' C F ~ C ~ armies r~ouid not havc uwii, all

of m~hich tvould increase thc elt-ment of surprise Rapid movement, hcridrs

benefiting tactical and aperational rnanem'er, alw irrcrearcd thix, and tz'as

achieved by forced marchcr Thc Spartan ccluipnient and awtcrc logirtic~ allorvcd

troops to move at comparatively high cipced twet terrain that ll'crtcrn ar~nies

would con~idcr diffictdt for large fnrc~5

'I he !!A also placed complctc faith in s e i ~ h i n , its strength of and spirit ovcr the

ttrntt;ritll superiority of it3 t.nemic\ N'hile hkstem thought tcrldcd to d i m i n stlch

intan~iblc a5pcct\, often pointing to several l a ~ ~ n e r e tli*iartcrs I ~ r o ~ ~ ~ f i t ahout I I ~

mirpli~ccd faith in this, it war nonetl~c.lcss at1 influct~cir~): Ihctc~r, with cei-ta!n

limitatiot~r Belief In this rms so rtron): and t hc lapanere ~ l t i i t r l To harticned 'to

ficld conditions that svirlrirl certain!! cnnrributcd to man?' of the teatr of

endurance that astounded Wc~tern opponents I~cgardlc.ss of thy clals system and

thr separation batwccn officcrr and nlcn, japancsc officcrs ~ i t l i n g t y shared thc

pcrifr ob combat wit11 their troops Oftiucrs led fronl the front, and a t much highcr

eclielonr than war common arnong thcir \\$?tern coiln terpartr Command ports

wcre clften Itxated h~rther forrvard than IX'v5tern pmctice Officers were required

to br as physicallv and mentally tough nr, their men The Japane~e cnunteratlacL

in the first dayr c l f the 19-14 Guam landing i$ a htting cxnmplc of thi5 :\haul

'1.5 percent of thr attacking unit5* officers were killed inclt~ding mwt company and

hattalion coommmandcrr, a l o n ~ with the coinn~ander\ of the attacking I~rigadc and

two rcgiinent5 The fint crpcricnccr that US troopr encountered of Jayanew

troops fighting to the death on 'I'uIagi and C;armtu-Tanabogo Islands on Atrgurt 7 ,

1942, came as a hock S o m ~ 900 SNLF, canrtruction, and air service troop5

d c f ~ n d d these thrw tiny islands acrnrr The Slnt frnm Guadalcanal .4bout 70

r m p e d hy qt\'imrning t'n larger Flnridn Island, 2.7 priqoners were taken, and

the rest died fighting Thc three Marine assault Iwttalionq Ion 145 dcnd and 194

wounded It nraF a rohcring experience and rtiouId prove to he the norm An cnrlicr

instance of this, rrlien a Japanese battalion landcd bchind US-FiIipinn lines on

Rataan in J a n u a y 1942 was not commonly knmm of by .r\rncricnn trnops

reconquering the Pacific The trapped battalion of 900 mcu fought to the death

without a sir~glc man surrcnderitm

Tlie Japanese often violared certain fundamental principlcr of drxtrinc Their

biggest failurc war to undercrtirnatr the enemy, especially foIIorving an initial

succesc Thip was a combination of overconfidence, arrogance, ant! over-reliance

on the strength of spirit The expectation w a s that the encrny would do arlapancsr

plans had prcdicted: the lapanese themseltes wcrc often tor, inflcsihlc to adapt to

unanticipated enemy reactions Often, another serious tlalv rvm the lack of recon-

naisFancc Zl'hile detailed reconnaissance was estal~lisl~cd doctrine, in ~rrrictice,

with the nlsh to attack, it was often neglcctd or based on i~nsealistic e%timare5,

rvith dire consequencer :\nnthcr arca in whicll thcrr rvere revere ~hortf;lll\ war

log~stics Sfany staff officcss fclt Ivgirtical concerns wcre Iwneat h 1 hem an J fncrned

on tlffensive planning Thc early operatinns against unprepared cnemy torccq tvilrp

successfi~l In spite of marginal logrrtics support, reinforcing t h i s belief

Complete ar111i hilatinn nf the cncmy war the goal sought in moqt opcratian5

:lllowinl: thc enemy to eqcnpe to fight again was unar;ccl)tablc This of course

rcwltcd m t t ~ e surrender of large nrln~herr of :Illid priqnncn, wlin did nnt light

to t % ~ c death as the Japanere ciid a n d rvl~o c t ~ l d not hc cnsilv di5porrd of, a% the

Chincw wrrc The concluenng of cok)nial tcrri toricr a l w meant that large

tluml~crr af 12krtrrri civilian< neere interned, for which the Japanese were totally

unprepared 'I'he treatment of prisoners anti inten~cer laricd ~ e a t l y depending on

A well-known photo of vrctorlous blsc Infantry tmaps on

Corregrdor-Tenno Herho! Eunzoi!

(Long Live rhe Emperor? Hurrah!')

local commanders There was little guidance on such matters This was also often the case wfth matters such as the disposition of captured equipment and installations, the aeatment of local populations, local s e d y arrangements, and the establishment of effective defenses m occupied temtorie

Amphibious operations

The JJA#s amphibious doctrine was well developed long before the start of the

Greater East Asia War, a pmess that had begun in the 1920s Japan was one of the first countdes to recognize its importance, and a great deal of expenence had been gained during the conflict in Uuna where joint-landing operations were commonly conducted by the UA and UN Doctdnal development did not progress much after the mid-1930s though It remained focused on China and the USSR,

and was not as advanced as is often stated: operations were generally conducted

on a smaller scale and were less robust than later Allied operations However, the IJA did posses adequate landing craft and specialized shipping engineer units to supportsuch operations

While the 1IA took the l&d in am~hibious doctrine and l a n mcraft desiRn,

the latter i&encing early Allied designs, the IJN also develGed doctrine Regardless of the IJA's and IJN's much touted rivalry, a joint dochine was created and the early-war landings were successfully accomplished This joint doctrine called for thorough planning; reconnaissance of the landing areas; a sequence of assault unit, reserve and suppon landings; rehearsals; naval gunfirr and air support; and deception procedures The cross-loading of transports was aitical, f o ~

example, so that the loss of any one ship would not mean the loss of an entire

unit Supplies and equipment were loaded to allow their debarkation

Mlhuru I d SNLF landing sits: he, a c c o k g to the prior it^ of need

Huon Gulf, northeast Now Gulnea, The naval force conducting the landing operation, usually designated the

March 8.1942 "occupahon force," was responsible for the overall operation The escort force

- Landing ~%3 I

commander, superior to the convoy commander, provided fire and air support

The convoy commander was respnsihle for the embarkation, movement, and

debarkation of the landing force The Army transport officer commanded the

shipping engineers and other mops supporting the debarkation

To maintain surprise, reconnaissance elements were seldom landed I

Reconnaissance was usually conducted by sutveillance &om the sea and air Often

after recomaissance andassessment of the enemy s i W o n Transport anchorages

and landing sites were often selected by running fast patrol boats through the

inshore area Every effort was made to land unopposed Then were instances

forces simply shifted to another site; after landmg, they thenattempted to endrde

the defenders from the rear The Japanese conducted very few opposed landings

and nothing comparable to those undertaken by the US, such as Tarawa, Saipan,

and Pel&u In most instances the only resistance encountered fame from d e r y

fire and air attack However, a major goal of Japanese landing operations was to

gam Local sea and air superiority

The actual landing was almost always conducted in darkness, just before dawn

or even eailler (most Allied landings were conducted well after dawn) This led to

conkol problems and confusion on the beach, factan outweighed by increased

surprise and protection of the landing force from d e r y and air attack There

were several examples of the defenders expecting daylight landings, only to

k d themselves ovemm before dawn If a daylight landing were required, ship

generated smoke would blind defenden and sueen the approaching landingaaft

Another significant difference between Japanese and Allied landings was that the The Port

Morerbl inmion plan,

Japanese would not land units on adjoining beaches; instead, they would land Mv 9, 1941 Even in an amphib,our

on sites often widely separated from each other For example, four forces were IS*^ dorrrine of flanking and

landed on Guam with anything from five to 20 miles separating them On some enveloping the enemy can be seen

- *- ' =

A - the \Ilierl ~~rdc-ticc c ~ t f i n t e5t:jblirhing a beach heail,

- < I of o ~ " l t i O n s \nothcr major dillcrrnre hrbven

The 49ft Type A landrng barge, or

Da~sutsu was the mosr commonly

used model by the IjA It was

powered by a 6-cylinder gasoline or

d~esel engine, giving ~t a top speed

of 8-10 knots Ir rnqghr be armed

wlth two LMGs and could carry

700-120 men.or I 0 horse5,or an

arcrllery piece, or a light tank, or a

I1gh1 rruck.There was also a longer-

ranged IjN version of theType A

Japanese landlng openrions

relred hcav~ly on manpower for

oflload~ng supplies and equipment

Motorizat~on was Ilrnited Here

shipprng engineers drag a ruck

ashore from a Type A landrng barge

Japaneqe and .\llied landirrgr war that only rhort prepamtor! naval gunfire barrages were Bred, crffen only after the landing trnopq

wcrc crnh;rrkctl, in contra3t tn prolonged Illid hnn117ardrnents

Otlcn a n SYLI', its size tailorcd for the specific operation, rvo~ild serve a>

thc first-tvavc assault troop< to establish thc ~iiitinl landing rite or reize a Ley

rrhicctivc : \ m y troop5 would follow it ashore or land sirn~lltnncorrsly etrewherc

tn complete the operatlnn I a t ~ d i n ~ craft rvould arsemble in a colismn fortnation tor their run ashore tn pro\-idc Inore protectirln boin fire Stem iightr nidcd

t>rientation lurt qhnrt of 5horc the craft moved Into a 11ne formatlnn I f oppo5ition

cspectctl they would olicn ltrc rvi tli machine plnc during the approach 'The

asrnult trtmpr n*ottld advance ar quickly as possible across the beach to the ncarest a\*ailahlc cover i \ ~ ~ ~ u l t c~mpanirs a n d hattaliofis d ~ d not maintain a r c ~ r v c , nlI wI,l~nit? r w r c i t 1 t h e Iinc Machine-gun i n f a n t r y - p n , and mortar unitr wo~tld

acc-nmpnny the assault units rincc artillen- could 11clt hc landeti until later The anaul t trnclps w o ~ ~ l d move as ql~ickl! a5 p m ~ i hle to wize the initial obiecthes sudl

a5 a ~ m r t , airfield, town, garrison, or roads leading to objectiiTer further inland

l t l f a ~ ~ t r v rcscrvcr, artillen; and endneers rvould follow ashore, transported by the

fint wave'% returning landing craft Oncc thc senior 4r1ny cc~mrnandcr asharc was

cestairl he could Ilold the bcauhc%, he anumcd command of oprratiuns ashore,

relieving thc 5m-y occupation force commander of rcspnnsihilitl; U u r i n ~ claylight morc tmops, scnricc r~nits and et Icxt 10-dal;~' supplies would he landetl, l'hc

transports would typically dcpart the area as roclrl a\ rleharkation w a s cc~rnplctcd

for fear of air attack

In t h e late-19205 the Sth, I l th, and 12th divlslnns were dc5ignntccl for arnphillious training Therc d i v i s i o ~ ~ s were stationed near Uiina, H i r o ~ h i r n a ' ~ p r t , home of thc JJ:\'s Shipping Engincer Command and the port horn which

cxpedirionarl; forccr wcrc Inunchccl Thew cli~'isions were con~niittcd tn China aftvr ~ E I C h c ~ i n n i n g of thc China Incident In 193 7 the xpactit'ated 18th Divi5ion replaced thc 1 1 th as an amphiliious divirinn lVhFle t h e ~ e diuisiilns collducterl iiniphiRinus uperiitionr in China, mort ended up in Manchuria Only the 5th

u+nuld scc action in the Pacific LVar, Other divirionr though were t o conduct

landings In China, rush ar bhe Sd, hth l h t h , and 114th

- Hctrveen 1y.5 / a n d I Y+ I rlxteen lnul tip~e-t~at tallon to alvlslon-

1 dzr landings w r e executed in China

P

.' 1 19205, t h e ramped Ilc~iartsrr r49ft, 10(F-120 troops) and the

I ramplesl KoEmtrrr (30ft, 40 troops) More advanced than any

period landing cmft, the 15.4 conducted no further d~\~c!npment

craff dcvelnprnrllt cnnri~lued tl~roughout rhc war, 5Shipping

erlginecr reglmcntr operated these and othcr landing craft, cach

with 150-2CX) craft and up ttl 1,200 troops orpnizcd into threc companicr Debarkation units consisted of some I,(hY) troops

1 assisting thc loading and llnloading of tranrports

qtructure, hut they ver)l much adjusted unit organization to suit their netdr, ln regards to "standard" tal~les of o r g a n i t a t ~ o n , thc lapancsc could have two or more for any given unit a s w e l l a5 variaticlnt of thcsc Ir depended on what the

unit's mission was and available resources \\,hen it war activated The number

of crew-s~rved weapons assigned to a g k c n unit might bc lesr or niore than the standard ertablisliment

The translatic~n or Jalarrcse unit designations wa5 often curnipted eiirl?' In tlie war as t h e interprctcrr, mostly Japancsc-Amcricanr (Sircir \zoith little r n i I i t a ~ expcrienuc, nFould translate unit dcsignntions without reference to any comrncln

~ t a n d a r d This rcs~ilted i n the sanlc types af units somctimt.5 he in^ identified hy two o r fhrec conflicting titles -\nototP~cr pral>lem war that qnmc inteIli~cnce

a n a l p t r attempted to assign Japanesc ttnits cqt~ivalcnt US deri~nation5 ~ i v i n g

them mislrading functional titles

[!A brancl~cts, of sen'ice were divided into tlie L i n e -1trns ( H ~ i k t ~ ) : infantry, artillcr!~ {.l~eld, rncrunta~n, m e d m m , heavy, coa5t, A:\), cavalry (horse, reconnaissance, tank) infantry mortar engineer, chemica1, transport ~ h o r ~ e , motor), railway, nletearoIogical, and air wruicc 'l'lie Sert+ices I Kitk~rt)rr~ included

the following: intendance, technical rortlnance,, medical, veterinary, judiciat and militarv band

4rmy level

"Gmups of armies" were derignaied by names usually defining their area of nperationr (for example, the Snutliern, Kwaotung, and China Expeditionan anniex) Thc group of armies wax roughIy equir.alent to an :\llicd theater of operation as it would cover forces re~ponsible for a broad arca The MnrtI?

China Area Army existed prior to the war It tcas not until thc rLlrnnlcr of 1942 that numbered area armies began, to be activated The "arca army" 'IHor?1rr~~rirt3 roughly corresponded to an ;\IIicd field army, but rr7as ~ t s ~ t a l l y tied to its

assigned area, in effect a sub-command of a group of armies It consisted ot

one or more armicr, air ilnits, and tvould hare rome dl\-isions and brigade5 under its direct control l'htt "army" ~ G ~ r r i ) w a s cqui\*alent to an :\Ilied corps

consistizlg of two to four dit4isions (some may have had only one or up tn six) p l ~ ~ s army troops (combat support and senice 11nits1 Any number of

independent mixed brigades might be assigned .+rmic.s were num hcrtbd, but

there were aIw named ;trmjes tied t o their area of rcspnnsibilitv (ruch as the Chosen and Formosa armies, for example); these should ntlt he confused with

Hrnr~r~xrrrr area armies "Distrir? armies" were purely at! tninirtrative comnlandr

c o n t m l l ~ n g u n ~ t s in the Home Island< and serponsible for m d ~ i l i z a t i n n , training, and forming nctr units

Di\.isional level a n d h c l o w

Infantrv ditrisions ( S r r i t l t r ~ t I sverr numhered and did not include "infantry" within their designations [Jit'irinns wcrc not r~eccrgarily n i ~ n l t ~ e r e d in the

IJA parachure mops sleeve insignia

This Insignia was seldom worn in

combat

Special Naval Landing Force

pnchuw mops insignia

The Imperial Guards D~vis~on

displayed this insignia on that

caps, as opposed to the simple scar

worn by other uniu

sequence in which they were activated and some numbers were skipped Depot divisions (Rusu Saidan) were found beaxing the same numbers as infantry divisions Divisions were sometimes known by their home district, such as the 2d or Sendai Division Infantry regiments were originally assigned to divisions

triangularized from 1936, with units deactivated, reactivated and reorganized

Divisions raised in the iate-1930s and during the war were often assigned infantry regiments in numeric sequence Infantry groups assigned to divisions and most divisional units bore the parent division's numbec For the most part,

divlsionai artillery resments d ~ d not coincide with the division's number

Regiments and independent battalions were numbered in sequence by branch

or functional designation The term "independent" ( D o W u ) defined brigades,

regiments, battalions, and smaller units not organic to divisions "Mixed" (Konsd)

referred to a composite or combined arms unit rather than a unit compris@ organic subunits of the same branch

Infantry brigades organic to a square division, usually numbered in

sequence, consisted of two'infantry regunents An independent mixed brigade (IMB) usually consisted of several independent infantry battalions (IIB) and organic artillery, w e e r , and signal units

Infantry and artillery regiments consisted of three organic battalions designated by Roman numbers (I-III) Abed intelligence usuaIly identified them with Arabic numbers Rifle and andlery companies were Arabic-numbered in sequence through the regiment or independent battalion The Japanese did not use the term "battery" but rather "company." Allied intelligence usually designated artjllery and AA companies as batteries though Battallon machine- gun companies were designated, for example, Machine Gun Company, I Battalion, 16th Infantry The same applied to companies organic to a regiment

for example, AT Company, 16th Infantry Antiaimaft and some other types

of regiments often had two battalions In this book infantry, cavalry,

reconnaissance, field artillery, mountain artillery, heavy adlery, tank, and

engineer regimental designations do not include the word "regiment" (for example, 144th Infantry)

Tank, reconnaissance, cavalry, engineer, shipping engineer, signal, and many transport regiments were actually battalion-sLze, being composed of

term "unit' (Tai or Butai) is often encountered A "unit" could range in size

from a platoon to a battalion or larger support unit They might be organic to

a division, or an IMB, or be independent

There were no resewations with regard to attaching units from one formation

to another in order to facilitate deployment and accomplish a given mssion,

even between divisions and regiments With hmited mathiel resources, the

Japanese pooled weapons in independent units that were assigned to area

armies and armies These units or detached subunits would be attached to

divisions and smaller units as required by the mission A deployed division

could have well over a dozen smaller supporting units attached There was no

set standard, nor "habitual attachments."

Early in the war most triangular divisions still possessed an infantry group

headquarters This was often detached along with a single infantry regiment,

artillery battalion, engineer company, and other supporting units to conduct

an independent mission It might be identiiied by its group designahon or as a

"detachment" preceded by the group commander's name; for example, Kimura

Detachment Reinforced regiments and battalions could also be detached for

similar independent operations Such special detachments (Shitai) were

essentially task forces ranging in size from battalion to division The Allies

usually called them 'forces" or "detachments." A number of such detachments

were formed £tom detached regiments and battalions for use in the Southern

Operations During prolonged operations their attached units could change

machine-gun companies w m attached to battalions and rine companies as

required Support units £tom higher echelons were seldom allocated to

subordinate units on an equal basis to the divisions within an army or to a

divisional lcvcl to a division's infantry regiments, for example, clcpcndcd on cach

segimcnt'r mi wion 'l'hc rli~irion did habihlally attach an engineer

rncrtical unit (Eittcr company, zrmrmmt and ambulance plator'lns!, and radio and

t ~ l c p h ~ n c ~cctio~i\ lo rcgi~nentr

-I'lic nrganizntion r ~ t divirionc varied greatly a n d depended not nnl y nn the

ti tne and place a c t i v ~ tcd hut the divis~on 'r torecart niisrlnn lapan" resources were ruch that it did not haye [lie lusury nf nrganirlng all ot its divilcms a5 fully equipped gcneral purpose formations capal~lc of ~~erforrning al! rnis5ionr Some "security rlivisionq" tCllinrr Slrirk??l~ ~ \ ~ e r c organized rvit ti tewer heavy tveaponr and lack in^ certain support components, as they were intended

fc~r garrrron (occupation t, an ti-bandit, or line-of-communication securiv

\l:liile on the one hand conserving resources, nn the other i t rneant that less than capable d i ~ ~ i s i o n r rverc deployed to combat roncs tvlien rcinforcen~ent

war necermry It also caused rome difficult! in tactical planning and rnirsion mrignments a% some of rheqe divi~ions were not trian~ularIy organized and

were differently a m c d from the "standard" division The 1st-2(lth Ic tcept

13th 1 jth, 17th, 18th) divisions and t t ~ e 2d Guards Division were considered permanent division5 ( $ o - ~ t , t s l t Sliidrrtf) Others were classified as temporary divisions i f i r k r r s ~ t r r t S l l i J ~ ~ l

J'hrec infantry divisions were motorized to some degrec In January 1041 Ln adriiticm to hcing trained for arnphihinus clpcrationr, thc square 5th and

18th diricions and the triangillar Guards Divirion rcccivcd vaning quantitics

of additional motor transport The 5th had 860 trucks, making it the most heavily motorized, hut it xtill had far fewer trucks than many Furopcan divisionr The 1Stti t ~ a d even fctws and still telied heavily on horse-drawn artillery a n d transport The Guards Division, rrnallcr in strength, lrad

660 trucks Due to this motnri7atior1, it was no accidctit that tllese divisions were committed to Malava The 4Kth had a slightly higher percentage of

trucks as wcll ;\ standard triangular d i ~ i s i a n at f i l l 1 complement hart only 200

trticks; mnnv posscrrcd far less

Triangular cIiuisions (Slrrr-tm-i Sltilliltr F wcrc first psoposcd in 1921 and called for thc elimination of the two brigade hcadquartcrf, deactivation nf one

regimcnt and t tic reduction of tlie battalions' four cornpatlie5 to three-a

nci v a v i n ~ of approximately six divisions of troops Cnnriilered ton drastic a reduction, only one cnnlpany *.a? cut from each infantry Ilattalir~n and one companv from tach cavalrv rcginicnt reducing thc Arm)' is? 60,nOOO men The coqt ~avings allowed a rnachinc-gun compnny tn he added to each infantry regiment and cavalry brigade raircd

The deactivation o r flve divi~ions in 1925 resulted in serious morale problems for officers rvho ithere a35igned tn a rcgirnent far life Only s~nall numbers of officers acllieved general officer rank ant! higher staff arrignrnents Unit officers

were seconded to training and rchool arriprnent5, but usually returned to their parent regiment Officcr~ of Ihc deactivatcrrl redments were reassigned to others,

ht~t alwa!.~ felt li kc ou tsfdrrs This problem was encountered again d l ~ r i n ~ the war when units were split from the parent segisncnts and divisions as cxpeditinnar>l units, or used to form ntrv unitr

I)n paper, the 1940 standard I<, or Ot?rr, trinrig~tlar i n f a n t y division consisted

of 20,000 troops, although this could he anyttiing from 18,000-21,001) troops This depended tm the rpccific assigned uni tr, as there werc severaI alternatives The division 1 1 9 coi~sistcd of t h e gc.neral staff and administrative staff

sections plus small guard, signal, ordnanctl, and veterinary cletachments along with a small I.IQ train for transport and baggagc The infantry group ( H ~ ~ l ~ i , i i l [ ~ r t )

HQ in clirect charge of thc thrce infantry rcglmcnts, had an administrative staff,

@lard detachment, and small H(> train Some infantry groups had a tankettc cornpan! (Ki~isukml~n CErirtni) with 10-1 7 r n a c h i l ~ gun-armed tan kettes

Table 4: standard B infantry dCvision

Standard unit Smngth (oficerfEMltotal) Alternate unit Strength (oficerlEMltotal)

Infantry p u p HQ' 10185195 Moy have k e n deleted

Tankette company c.80- I ZO tom1 Moy h o w been deleted

Infantry regment ( ~ 3 ) ~ 1 1313.73213.845 Infantry regimenr ( ~ 3 ) ' 10 113,17413.235

Artillery group HQ' c 160 total

FA regiment 80~02012.lOO Mountain artillery rep 9 113,40913,500

T a n k e ~ e company5 c.86120 total

i Eng~neer regiment 2519251950

Transport regiment SO1 1.7601 1.8 I 0

Ordnance d q unit 61104F110

Division medical service

Medical unit 401E,0701S.I I 0

Field hospital (x4) 251225flSO

Water supply unit 1 112241235

Veterinary hospltal 10110511 15

I

Notes

' Guards 2d, 2 ISS 38th 48th and 56th divismnn only

5uttuImns with four nfle companies

' BottoI~ons with thm rifle mmponrw

Assigned on!y to Guards and 2d divisions

"ormolly ossigned to the infunny group

Standard B triangular infantry division

Infantry dMsion headquarters

The infantry regiment

The infantry regiment (Hohei Rentai), comprising roughly 3,800 troops and

over 700 horses, was a well-balanced unit requiring few attachments to be

effective in combat Its basic organization remained constant throughout the

war, but many variations of subunit internal organization and the types and allocation of crew-served weapons can be found Organic medical support was

light, with two surgeons and two orderlies in the regimental administrative section, three surgeons and four orderlies in each battahon, and four orderlies

in each company Additional medical support was attached from the division

It must be noted that the following strength figuw represent typical une strength; the actual strength in the field varied greatly and few intelligence documents agree with each other on this matter Note also that when numbers are

provided the flrst number refers to officers and the second to NCOs and enlisted men Where only one number is shown, it refers to NCOs and enlisted men

The regimental HQ consisted of the staff, administrative (2/16), code and

inkU@nce (1110) ordnance (118) intendance (114) and LMG sections (5) plus a

color guard (115) The staff, such that it was, consisted only of the commander,

opeations officer, adjutant, and gas offim It also indudeda 121-man regimental

tpain with field and ammmMon sections The 40-man 5eld section had 30 one-

horse we-wheel carts or 40 packhorsss It carrieda day'srations for the regimental

companies along with headquarters supplies and equipment A field kitchen from

the division might be attached The 81-man ammunition section W e d a days

or on 120 packhmes

THE W ~ m n 4 ~ 0 ~ Y

The three, roughly 1,lWman infantry ba'ttalio~ (HoheiDaitaiJ had a 30-man HQ

o~dnance and intendance (2/3), liaison (4), and LMG sections (5) The 110-man

battalion train had a 50-man field section and a 60-man ammunition &on with

horse carts or packhorses Thebanalion trains were sometimes combinedwith the

regimental train A labor unit of 1W-200 men organized into six sections plus an

equipment section augmented some regiments, This was by no means a standard

fixture More often than not, labor details wwe drawn &om the infanuybattalions

or from external labor units -

THl l<bll I < O\Il1\YY 'The four, 180-man rifle comp;1nic5 hail a 1 ~ - m a n HQ with the cninri~n~~dcr, a

pcrfonnel warrant officer (equivalent to an csccrttil'e o r i~drn~r~ishative cifl~ccr), a

Tcrgennt malor In c l ~ a r ~ c of 1~crwmncI r r c o r t i ~ crr~ughly e t l u a t i n ~ tn n firft-

Platwn heaaadqttarlm Legend

a Platwn commander (piston f Second machrne gunner (pjsfoll ~ l ~ ~ c o ~ a r r n e + pslok usualh meld * rrllH

b h a m serqeanl tr~llel a Thrrd m ~ h m e gunner IplsfolI hhchlne g ~ m n m WFW amd

c Section leader (r~fle) h Affleman O ~ I V wltn L M G ~

d LMG crew leader lplstol) i Grenad~er (grenade discharger)

B Mach~ne gunner lplstol) j Second grenadter (riRe1

1st lIgM machlna gun seem

Zd llgM machime gun d o n

36 light machine gun section

sergeant), a rupply sergeant a n arms and equipment sergeant, four medical ordcrlics, a n officcr'r ordcrl!; b ~ ~ g l e r , and eight rneuengers The three, 54-man rifle platoons had a two-man H Q witti a platoon cornmantler and a liaison sergeant

Rnughly equating to a US platoon srrprant, the latter's mail1 duty rrras to cnsure

orders wcre relayed to the sections through arm signals and mcsscngcn Thc threc,

13-man light nlachine-gun sections ivcrC I t r l hy c o r p c ~ n l ~ F ~ c h cnngi~tcd of eight

iflemen and a four-man rnachrne-fl~n crew: the latlcr r+onsistcd of a crcw [cadcr, machine hwnner and ~econd and third gunners (ammunition bearerr) All four of

the crew were armed with p i ~ t o l a hut in practice often carricd rifles One rifleman usually carrier1 a rifle-gwnadc launci~er Ircctinnx awignccl to rtrengthez'ted units had the addition of a two-man 5cm grenade-discharger crew Designating the section "light machine-gin" rather than "rifle" cmplia~izcd the fr>nrr on the machine Run as the firc hart for the section, a n d i h c role of the ritlc~nrn in protect in^ it T h c grc'nade-disct~ar~cr ~ c c t i o n n r a ~ Icd hy a coq~nral and had three, two-man gwnsdc-discharger c r r ~ plus six riflemen, w t ~ o also carried ammunition The grenadicrr rverc armed on\! ~vitti ttie disctiarger and a Iwyonet, hut .innle may havc carried rifler Ten- lo h\,ulve-nlan qertions were common In combat, wticn rtrength dwindled the grenadc-discharger sechon w a ~ usually ahsnrhed into the LMG sections

Some ba ttalic~ns lrad only three rifle ct)~-tipilnim, though most still had four early in the \I-~r Though not a normal fixture sume strenflhened companies had

a 46-man weapons platoon This would Iiave two HMGs and 2cm .AT rifles each manned hy an 1 1-man section 15 ruch a platoon wcrc arrigned, the !r;capons were reallocated from the I>attalion m a c h i n e - n ~ n company and infantry-gun platoon, as oppowd tn having the allocation increased

0 I HFR 14.\l-te\l 103- 4YE1 RFr;l\ff \T\I -1 FYF1 CYTI'F

The standard 174-man hattalion machine-pn company had a 1 4 m a n HQ and three machine-gun platoons 'The platoon^ had n hvo-man FIQ and foils 1 1-nian sec-tions, each rvith an HMG for a total of 17 hut some had only eight HMGr There was also a 2 Z m a n ammunition platoon Complete platoons migilt he attached to thc forward companies nr pain of gun$ [night be attached Some

HMGs were retained rlnder battalion contml Rattalior~s featuring company

weapons platoons, with nvtl H5IC;s assigned to cach, wcrc organized intcl ttw,

74-man HbILil; platonllr of trrro sections m c h pEw a 15-man arnnli~nition platoon Thc 55-man battalion gun platuon had a 10-man HQ, a 15-man ammilnitinn rectian, and ttvn 2 5-man s i n scaions, each with a Jcm infdnty gun I\ fvw units

possesred a 122-man battalion gun company a 27-man ammunition platoon, and two 31-man gun platoons, each t ~ i t h hvo i c ~ n infantry gun5 Units fomlnatc ennugh to be provided I c m :IT rifles ~ ~ o u l d also have tnur :IT rifle plntonn? addcd

to the gun company along with an enlarged 39-man ammunition platoon Fach

21-man platnnr~ had a two-man H Q and nra 11-man scctlonr, each manning an

AT rifle TIlerc platoons did not cxist if tllc :IT rifles rwrc assigned to riff c company

w c a p n r platoon$

Several cornpan! size unitr t.crc directly under re~irnental control, enhancing itr combat capabilitier The 122-man rcdnicntal company had a 25-man HQ

an oh~crvation wctinn, a 3 3 -man ammunition platcx~n and tllrerr 33-inan gun

platotoon~ Gun platnanr had try0 15-man n l n sectinnr, each 1 ~ 1 t h a 7 5 ~ ~ 1 1 infantry pyn A few regiment< Ilad 364-man regimental k%n battalion5 nlith two 1 70-man four-,qun companies and a 2-1-man t-lQ

The regimental Xf company had 122 men in a 20-man FIQ a 21-man

ammunition platoon, and three 25-man :IT gun platm>ns, each with hzro .+.7cn1

AT' gunr manned hy I I -man sections Some low-priority unitr had tM.0 3.7cni :YI'

p ~ n r in the regimental gun cornpany along rcitti only huo 7.5cm regimental ~ J I I S Tile 132-man regimental sig!lal conlpany rvar orga~iizcd into a 3n-man MQ,

a telephone platoon with four t o sis sectinrrr each with three tclepironcs and

a sn~itchhoard, and a radio platoon with five to eight scctions cach operating

one radio, The telephone and mdlo seetiom were attached to battalions and

Field and mountain artillery regiments

The Z,X&man fi@d aWery (FA) 'regbent (rahuhei RenkrF) had a v q d HQ,

an obmmtion group, a regimental train with a fleld and three ammunition

sections, and Mree W m a n W e r y baW011~ These had a small flQ,

tio on group, battalion wain, and thzee azWmy mmpaniw A m p a n y had

7 5 ~ ~ guns manned by 19 men, givlag a Qtal of 3FjhoMtzetS ThW w&e about

2,OM) horses assigned to the regiment fot ,towing, guns, and ammunition and baggage carts The regmental, battalian, and company o b a w t i ~ n group had

obsenqtioi~ and arepd plsudons, WMch became progresSavely smaller at each

echelon Some regiments may have had one 7.&i bampn replacqd by a

lOnn h o w i i W o n ?he &-man mountaixi artUlerp WUIem (Smnpoho'

Rmtfli) war organized much the same way as the FA regiment It was equippd

with thirty-six 7.5cm mountain guns, which were transported by 1,400 draft and

packhorses A crew of 24 manned each mountain gun

Reconnaissance and cavaEry regiments

The 730-man reconnaissance regiment (Subnbr Rottni) was a cavalv-branch

unit, which gradually replaced the cavalry regirnmt as the war progresrcd, It

consisted of a 130-man HQ and train, a mot~nted company, two truck-borne

companies, a tankett~ or armored car company, and a truck transport company

The 130-man mounted company had four 30-man platoons Few regiments

actually possessed the tankette or armored car company A regimental company

had either seven tankettes or armored cars The I hl)-man truckborne companies

had two S&rnan platoons organized and armed essentially the same as a rifle

ptatoon, a 24-man machine-gun platoon with huo HMGs, and a 24-man AT

platoon with rwe 3.7cm ATguns-which many units lacked The 100-man truck

transport company had kwo platoons, at least on paper, with one to transport

eac- h truc k-borne company,

The 950-man divisional cavalry regiment (Killpi R n i t ~ O had an 82-man HQ

and train, a machine-gun, and three rifle and saber companies The companies

had three platoons each amcd with three CMGr and nuo grenade dischargers

plus a machine-gun platoon with two MMGs The rnachlne-gun company had

two platoons each with two HMGs and two Zcm AT rifles plus a platoon of two

3 7 m AT guns and an ammunition platoon Although supplied with some 1 , 1 0

horses, it was not uncommon for these units to be dismounted later in the war

Engineer, ttanspott, and signals units

Thc 900-1,000-man engineer regiment (Kohd Rentni) had a 100-man H Q and

train and a matiriel platoon of 56100 troops The three engineer companies

had approximately 2.50 men in four SO-man platoons plus a 25-man nlnteri~E

section with trucks and some powered engineer equipment The platoons

had four sections each A company was habituallv attached to each infantry

regiment to provide basic obstacle dearing, light road repairr, footbridge

construction, and other minor tasks Non-divisional engineer regiments were

attached to divisions from army level far more specialized engineering tasks

Tranrport regiment (Shic!loltei Rmtni) organization varied greatly depending an

the number of trucks available IdeaIly it consisted of a truck transport battalion

and a draft transport battalion The truck battalion had two or three companies,

each with up to 50 truck of 1.5-ton capacity Many had fewer and some virtually

none other than comrnandccred vehicles 'l'hc draft hattalion had three or four

cornpanier, each with wme 240, two-wheel, single-horsedram carts and 350

A mountain artillery unit tnnrporting a 7.ScrnType 94 (1 934)

gun could cover up to 10-15 miles

a day.While much slower than

motorized ransport packhorse units could rraveT across terrain

impassable to trucks, such as

swamps, jungles and mountains A packhorse could carry a little under

3 0 0 Ibs.The drawback w a s that packhotse unit.$ r e q u i d more

m a n p w r and large quant~ties of fodder, resul~ing in supply problems

The @A fielded a wide m r i q of specialized engineer units Hand

tools were used for much of che work, bur some pclwered equipment was available like this German-built

F 32&model, diesel-powered,

8-wn mad roller.The scarc~ty of

equipment forced rhe Japanese

to limit the extent of therr

construcrion projem

.lC;CIVL Truck cranspon was

supply, and In Japanere d~visions was

on a much lower scale than m heir

European counrerpam A commonly

used 1.5-ton cargo mck was the lsmu

Type 94 (1 934).The rear wheels were

powered, but nor the front ones.which

hm~ted ~ t s cross-counry mobility

o1lZUT blst lnfanrry trcups cwer an

engineer as he sprap a Corregidor

bunker wrh aType 93 (1934)

flamedrower Slnce the Japanese did

nor use th~ckened fuel ~ t s range w a s

only 25-30 ydr

The primary means of ~crtwl

rransporr found a t all levels was the

one-horse, two-wheel cart which

could carry 400-500 Ibs of cargo Hew

additlcnal mules have been hitched to

the cart to drag ~t through mud In

occupied areas every moronzed

vehicle w a s confiscated for military use

trorrps \.Ian! regiments did nnt poam5 a bnttaZion smlcturc, but liad up to eight draft companicr plus a smaH r-eterinavv unit Such an cight-company regiment

nnrrnalls aIlooatrd four companies for rations and torage, hvo for artillcry ammunition, anti one for small-arnw an1 m~r!-rition In snme units packhosrc

cnrnpanies substituted draft cnn~paiiies on the har~s of hvn packliorse cornpanic5 tor one draft 'l'hcy had :{/I11 packhorws and 431 trnnl~s Ahout one-third nf tlte

tmops wexr armed

'rlic large company-\izr \ign.nal anit (Ilcv~rlarrtr~il lrad two telephone, one radin and a nrrit?rir~l platrlon plul a 20-inan H Q and mcrrenger section Thc SO-man telcl?hnnc platclc'ln~ each had lour ~rctians operating two telephones and s

srvitchhoard Thc TOO-man radio (~Iatoon had betrt-cen eight and twelve sc.ctbiis, each operating a radio The wire and radio srctionr were detailed to regiments and other divisional unit\ hrtiltery unitr pnsscs~cd organic signal elernen tr

thouxh The company-ri7e crt~fnatlce duty unit provided weapnn rcpalr and

technical services

Medical and veterinary services

The rlivi~ion nredical wryice, headed by a coloncl, nTas sizeablc In ortier to treat

casualties in f o n ~ a r t l areas This allott-cd the ri.oirndcd an earlier rcturn t o rlut!' ant! rcd~iccd c\racuation req~~irements I t included a medical staff qection in the

divirion staff T n c dit~isional medical unit lS/?i[Lrr~ Eireitni), commanded I>v a colonel or licutcnant-coloncl, Ilad a 265-man licadcli~arrcr~ providing v a r i o ~ ~ r

specialized medical, dental, and pharmawutical r c n l c c ~ pin7 three treatment platoon%, threc litter companies i20 litter tcanlr), and an amb~~lance company

1.45 amhulancesj tl litter company, treatment platoon and a~nht~lance platoon Iorineti a regimental medical unit for attachment to cacli infantry regiment

Division Infantry reg* Artillery reg Reconlcavalry r e g Engtneer regt Transport regt I

Guards 3.4.5 Guards Guards FA Guards Recon Guards Guards

They prnvidcil collectinn, initial treatment, arid cvaruntion to t tic field hospitals

Tor rvounded 5old1crr Thc three clr f o t ~ r , ,500-patient fielrl t~ospitalr I li7cor R~~uirr,

dcsignatcd lxt-4th in each dici%ion, cach had a nlrdical company to operate

thc hospital, perform surgvry, and trpat thc rick and wounded It also hacl a

tranrporr cnmpnny to haul etluipmc.rrt, supplier and pcrsonncl It provided

manpower to crtahlish the lio~ljital facilities in rpnts Thc large t4~atr.r-supply and

purificntic~n unit Incated, purilieci, ancl di~tributed water aq,plies a\ i\+cll ar

~ r r f o r m i n g marly pre\,rntivc mcdicnl and field hyglcnc tadis

The con~pany-size \.ctcrinary Ilt>~pital trcatcd ~ i c k , in jurcd, a n d wounded

h o r ~ c r It \$+;is also r c ~ p o n ~ i l ~ l e for advising on t h e care and fcetling of t h e

division's 7.5130 horses, ar even a hew I~untIred i l l horres could redlice ;I

di\,i5ion'r effectiveness I.crv medical and vetennary troops were armcd

7 he few wn~aining squarc divisiuns ( fisr-hrr~-l S I ~ l r i ~ r r ; ~ wcrc cplite large, coinprising

some 25,0013 troopr T l i q m t\+erc holclwcrs aftcr tlir 1q.3h reorganizalion whcn

the proccsr of trianplarimtion ~ c r t underway for most r l i ~ i ~ i o i ~ r 'l'hcy had twr,

infantry brigade (1blrr.i I*liln~l, I IQs, each with two infantn rcginrrnt~ (nnt to be

ronfured with the "brigaded division" clF trr-o tvigndcs witit fo11r FltZli apiccc, rvhicl~

will he divmsrcd in a subsequent lafumel Shc 5th Pivision's 5111 1.A Regiment

had bvo 7.5ctn battalions and a 10cm h o w i t ~ e r hattalion, rvliich were truck-

drarvn The 18th L>i\.ision's 18th 1Iountain "-1rtillen' hart thrcc hattnlirmr c ~ f

pack-tranqparted 7.5an mountain Duns Con~ponerlt unit5 rverr rinlilar tn the

triangular dir+iqrens, I,ut d i ~ h t l y higher in strenhqti and p$sesretl more truck

transport Tlie motorized 22d c:aualn Rattalion 122 Killri IJnihri, was sn~nller than

a cavalry regilncnt with 600 troop The 5th DitVi\ion w a s triann1lati7ed in earl!

1942 with the dctnchrncrlt of the 4tst I n f i i r r t ~ 'The 18th war r~r)rgarlitcd in April

1 Y43 with the 124th jnfantr?? detached and thc 27iI C a ~ a l v Rattalion diqbanded

Hnth diii5ions droppcti the hrigadr HQF

ibte 7: Southern Operations square divisions

IMBs were mainly intended for occupation duty and lineof-communication security Most had from three to six 1,000-man independent infantry battalions

OLB, Dokwitnr Hohei Daitaf), with five being typical, gvmg the IMB 6,150 men

It also had a 160-man HQ, 600-man battalion-size FA unit, 250-man engineer unit, and 140-man signal unit Other infantry brigade-sized units included

independent huktry brigades (Dokuritsu Hohei Ryodm) with four IIBs and no

support units; independknt infantry groups (Dokuritru Hoheidan) with three divisional-type infantry regiments and no support units (which later pmvided core troops for new divisions); independent mixed regiments (Dolarritsu Konset Rentai); and independent W t r y regiments (Dokuritru Hohei Rentai)

The two brigades employed in the Southern Operations featured a different organization though The 5,000-man 21st IMB, instead of IIBs, was assigned the 3,360-man 170th Infantry Regiment; a 140-man HQ 360-man artillery unit; engineer and signal units as other IMBs; a 130man tank unit with 11 light tanks;

a 110-man Zan AA unit; a 260man transport unit; and a 250-man field hospitaa The 6,659-man 65th Brigade (65 Ryodan, no other desdptive designation in

its title) was a unique unit consisting of the 1,920-man 122d, 141st, and 142d infantry regiments They initially had only two battalions and a gun company apiece and lacked an AT company The 65th was assigned company-size engineer and medical units, and a platoon-size signal unit

nst Independent Mixed Brigade

Standard towcompany tank regiment

i-

A 7th Tank Reg~ment Type 94 ( 1934)

medium tank crosses a hast~ly

repalred bridge en route ro Manila

Thc white five-po~nred star

ident~fied rhc I s t Cornpany.The

3d Company used a srar with round

"points" and the 4th Company

(L~ght) used the below ins~gnia

flank recurit? Some cornpan!? [ I Q h may lin%~r had I)HC o r two tankctte~ irl lieu

n l light t a n k 7'here wcrc imtances of p,latclons h a v ~ n g four or five tanks while

1)tht.r reeitncnt% were undcr~tren@h I tcrtv rcgirncnts had only thrcr light

ctlmpanicr \\.it h tl~rcc platoonr apiece Thc re~iinetlt possr5sed a truck-bornc

maintenance ctlrnpanv rind rach tank compnnv hacl a inotorized amtnuninion land h a g ~ n c c l train

'Fhc rc,qimcl~ts i r l Xlnlny were zlt~dcr Ihe ,311 Tank Group 13 S ~ ' ~ l ~ ~ l r l ~ ! l f l l ,

incorrectly cnlIed a "brigade*' 1 (;ruup~ were adminirtra tive licadrl~iarten

irrard~quate for tactical c o n t r t ~ l and were cl[nrinatcd in 19-12 The tank rcgimcntr

emplo>'ed i l l the Soutliern Opmtic>ns varier! grca tly in tenm of theit cnmplimcnt and internal org;rniration, a\ rhnr\.n in Tal~le 3

Table 8 Southern Operations tank regiments Malaya

6th Tank 37 xType 97 medium tanks Col Kawamura

~hilippines"

7thTank 34 xType 94 medium tanks Col Sonoda I

1 4 x Type 95 lighr canks Netherlands East lndies2

2d Tank (-) 3 1 x Type 97 medium nnks Col Mon

I

5 x M3 light e n b (captured) E!urrna3

Isr Company, 2dTank I 2 x Type 95 light tank LC Ohda

Notes:

1 ' Some cotured US M3 Iight conks were abo employed,

I 4th Tank Regiment orrived later fmm the Philippines

1st ond 4fh Tank regiments orrived in April 1942

Iactics

The close-combat traditions of the rce~~lrrrri efsentially lived 011 as Japan c~itcred

the modern age The a r r i r d of repeating riflrs, machine Run?, a n d brecch-loading

artillery did littlc to ciimini3h t h i ~ Whcn new field rna~~uars rvcrc pr~hlisheil i r l

t909, the infantry manual emplia5ized thr infantry attack preceded a barrage

nt rifle fire follo~vcd b a bayonet charge Ilrgartllers of the lersons learned at Port

Arthur, rz~here Japanese troops were mown down try machinr guns and nrtiller?'

it1 World War I fashion, combined arms rrarfarc rccondary The clthcr hrancli

rnanualr f o ~ ~ l s e d solcly nn >upporting the infantry attach

34achine gun5 were locaterl only a t rcgimcntal l r l ~ l until 1924 when the

liglit machinc gun war AcIded, m u c h Inter Lhan i ~ a i c d at ?quad level i n

We~tern annirrr The principle< of closc combat wit11 t h e b a ? ~ > n c t , advancing

in skirmish lincr;, and direct-firc artillery rwre adhcrcd tu iong after Itley rvere

abandoned in the Il'cst F l u ~ e r ~ e s it must he raid that Japanese quickly

embraced the IigF~t machine grin as a principai infantry tveapon and dcvelaped

all their small-unit tactits nrolind it Thi5 rvar especially apparcnt in thc I'acific

when, r.ouplcd with the grenade discharger anif protected by riflemen, there

weapon5 crcnlcd havoc among :\!lied troop$ in close-rangc jungle firefightr

Even in open terrain thc Japancse empharired closing rapidly with the enemy

arrd cngaging him in closc combat, to exploit their wpcrior rr,i\'lli~l, !+'hen facing

Allied forces this "httgfiing" tactic had the added benefit of lesrenirtg any artillrr)

and clow air s~rpport irdvarrta~c f o r fear of causing fricndly casual ties Tlre rugged

terrain and denre vegetation encountered in much of the Pacific and Southcart

Ada prc,r-idcrt an ideal, i f hanh and untorgiring, environment for clow-cambat

tacticx While moxt annics might ranrtion night attackr, the [I:\ war onc of tlic

fcrzo that pract~ued then1 ag~rc.\<irely and accompli~hcd them succeatully on a

regular baris

'1 he 11.4 placed great trust i n the enrrclcloping attack, rvlrich might takc rmc i ~ f se\+eral

fnrrnr: single envelopment t o une Bank, douhlc cnvelopinent to 110th Ranks, and

encirclement Envelopments attacked ~thc enemy's flank(^), nhilc encirclement

drove deeper to cut the enemy off from the rear lsornerirncs from only one flank)

At the rarne time pressure was applied to the enernv's front and flanks

A paratrooper of ine I s t Raidlng

Force mans a 7.7nm Type 99 (1939)

LMG.This wo-reg~ment 11.4 unlt execured lumps a t Palembang Sumatra and Koepang.T~mor In

1942

nent

Encirclement required a division-sued orlargerforce Divisions and regiments could conduct single and double envelopments The size of the Japanese force and its exaa deployment obviously depended on the strength, deployment, and composition of the enemy as well as the terrain The Japanese would often execute envelopments with forces numerically smaller than the Allies would have used though

The most common method of conducting an envelopment was to advance

in two or three parallel columns When contact was made with the enemy, one

or two columns would move to attack the flanks or rear This was the common means of an advance to engagement by a division A brigade or regiment might advance in one or two columns until making contact The lead elements would

place pressure on the enemy's front, a holding atta* while following units would endrcle to one or both flanks Another, though more complex method,

was to engage the enemy and move units through concealing terrain or under

the cover of darkness to attack the flanks Even a rlfle platoon, when meeting

from the flank

In Southeast Asia, the NU, and Philippines the Japanese would conduct enveloping movements 2 3 miles to the flanks of the Allied force and several miles deep They would establish battalion- and larger-sized roadblocks on the line-of-wmmunicatio~~~, and Allied units, finding such a large force in their rear and lacking sufficient tesetves, were forced to withdraw frontline units to

or infiltration at@& on the weakened force Infiltrating platoons, when

counterattacked, would simply go to ground in the dense wgmtion, allow the

attack to pass through, and engage the enemy from behind

Frontal attack

The UA cautioned against the fiontal attack, but in practice the Japanese kquently executed it This was often due to the overzealous desire to annihilate the enemy, but terraln and enemy dispositions might also prevent an enveloping

main assault, and the main attack would st&e here The goal was to penetrate deep into the enemy's rear and attack command posts, artillery, and services Tanks would be employed if available Artillery support was usually inadequate

and maximum use would be made of heavy machine guns, infantry guns,

and mortars

The division would normally advance in two columns, with a reinforced regiment in each The reserve regiment would move behind one of the lead

columns, depending on which flank the commander had antiapated would be

the most effective to envelop fmm I£ moving In three columns the third

column, situated on either flank as a screen or security force, usually consisted

of a reinforced battalion, which may have been detached from one of the lead regiments or the reserve These column6 might have been designated the left,