CHAPTER 3 - WWII JAPANESE FIELD ORGANIZATIONS - SECTION 1



TABLE OF CONTENTS







SECTION I - MAJOR ORGANIZATIONS



Note. In some cases in this chapter, sufficiently definite and comprehensive infomation has not been available to enable representatives of the participating headquarters to reach fullt agreed figures. Therefore, although the main structure of the Japanese organization is considered to be well established, some of the details are likely to need amendment in the light of future experience.

1. FIELD COMMAND.
The Japanese Army in the field is organized into groups of armies, area armies, armies, and forces with special missions which initially do not come under command of any army. The Chief of Staff of the Japanese Army is responsible for the general direction of the army forces in the field.

2. GROUPS OF ARMIES.
A group of armies, such as the Kwantung Army, might be considered the equivalent of the command of theater of operations.

3. AREA ARMIES.
An area army, such as the 8th Area Army, may be considered the equivalent of an American or British army.

4. ARMIES.
A Japanese army shuold be considered the equivalent of an American or British Corps. It is composed of a headquarters, a variable number of infantry divisions, and army troops. Such a force normally comprises from 50,000 to 150,000 officers and enlisted men, The 18th Army in the Southwest Pacific area during April 1943 had a nominal strebgth of about 130,000, but its actual strength was always greatly below this figure because of attrition enrouite, casualties, and detachments. It includes the following units:



3 Divisions - plus small elements of a fourth. 3 Independent motor transport battalions.
1 Independent mixed brigade. 6 Independent motor transport companies.
2 Infantry mortar battalions. 1 Signal unit.
4 Independent field antiaircraft artillery companies. 2 Fixed radio units.
6 Indeoendent field searchlight companies. 5 Line of communication hospitals.
6 Field antiaircraft artillery battalions. 1 Water purifying unit.
2 Field machine cannon companies. 2 Debarkation units.
1 Independent antitank gun battalion. 2 Anchorages.
1 Engineer group. 2 Construction duty companies.
7 Independent engineer regiments. 3 Land duty companies.
1 Independent engineer company. 5 Sea duty companies.
2 Field road construction units. 1 Water transport unit.
1 Field airfield construction unit. 5 Airfield battalions.
3 Field duty units. 3 Airfield companies.
3 Shipping engineer regiments. 2 Base forces (Naval troops).
1 Field motor transport depot. 1 Field freight depot.
2 Field transport commands. 1 Field ordnance depot.
1 Independent transport regiment. 4 Line-of-communication garrison (sector).




Figure 8. WWII Japanese Field Command Organizational chart.
Figure 9. WWII Japanese Staff Administration Organizational chart.


5. ARMY CORPS.


Japanese militay terminology does not include the term army corps (see par. 4).



6. INFANTRY DIVISION.



a. General
In its basic form the Japanese infantry division is composed as follows:

- Division headquarters.
- Division signal unit.
- Infantry group headquarters and 3 infantry regiments.
- Artillery regiment.
- Cavalry regiment or reconnaissance regiment.
- Engineer regiment.
- Medical unit.
- Field hospitals.
- Water-purification unit.
- Transport regiment.
- Ordnance unit.
- Veterinary unit.


b. Classification and strength.
Organic units of the Japanese division exhibit various differences in organization and strength, because they are organized for different roles and varying types of terrain. The Japanese themselves classify these organic units into three general categories:

A - or the strongest
B - representing the standard
C - the special



Figure 10. WWII Japanese "standard" triangular infantry division Chart.


Consequently the strength and classification of their divisions are largely dependant upon organization of their organic units. However, this does not constitute a hard-and-fast rule whereby all Japanese divisions are composed exclusively of any one type of units. For example, a basically standard, or "B" type, division often may have "A" type artillery. In addition, there are also strength differences within the division units themselves. in an "A" type infantry regiment, the regimental infantry gun unit could be either one company of four guns or two companies of four guns under a small battalion headquarters. In general, however, all Japanese divisions come within the following classifications:

(1) The standard division. This type of division has been encountered most frequently in present (1944) operational areas. It is composed of organic elements listed in paragraphs above.

(2) The strengthened division. This division is composed of "A" type units (augmented personnel and firepower) and may include an artillery group, consisting of a group headquarters, a field or mountain artillery regiment, and other artillery units; an organic tank unit; and a chemical or decontamination unitfor gas control. This type of division so far has not been encountered in its entirety in the field.

(3) The strengthened division (modified). Elements of this type of division were known to exist during the early stages of the war, and the division may have been a fore-runner of strengthened type described above. It includes an artillery group, but has no organic tank element or gas decontamination unit. The infantry rifle companies are found without the heavy weapon platoons of the strengthened type division, decreasing the rifle company strength from 262 to 205. In such case the heavy machine guns and antitank rifles are found in the machine gun and antitank companies.

(4) The special division. This is a lighter type of division composed of two brigades, each of four independent infantry battalions supported by small units of auxiliary troops (mainly "C" type units). The future operational role of this type of division is difficult to forecast, but to date it has been found employed in garrison and antiguerilla activities in China.

c. Charts and tables.
The following charts and tables depict the organization of the four types of infantry divisions listed above. However, in view of the many possible combinations of types of units within a division, these charts and tables cannot be taken as exact models for all divisions. Following the charts and tables are presented detailed analyses of organization and strength. Where known, variants are included. Emphasis has been placed, however, upon the standard division.






Figure 11. WWII Japanese "strengthened" triangular infantry division chart.




Figure 12. WWII Japanese "strengthened" (modified) triangular division chart.



Figure 13. Japanese Special Division. This type of division has been identified in China engaged in garrison and antiguerrilla operations.



Units Personnel Horses Rifles LMG HMG Grenade
discharger 		light
mortar 		70-mm Battalion
guns
Division headquarters 250 160 180 4 ----- ----- ----- -----
2 infantry brigades 9,500 1,000 5,600 100 32 100 16 8
Each 4,750 500 2,800 50 16 50 8 4
Signal unit 200 30 70 ----- ----- ----- ----- -----
Engineer unit 600 100 500 6 ----- 12 ----- -----
Transport unit 1,800 1,290 500 ----- ----- ----- ----- -----
Medical unit 650 80 100 ----- ----- ----- ----- -----
Total 13,000 2,660 6,950 110 32 112 16 8

Figure 14. Strength and weapons of Special Division (all figures are estimates as of 1944).





Units T/O Operational Horses Rifles LMG Grenade
dischargers 		HMG Machine cannon
or 20mm anti-tank rifle 		37-mm or 47mm
antitank gun 		70-mm Battalion
guns 		75-mm Regimental guns 75-mm fld or mtn guns Tankette or
armored car
Division headquarters 300 300 (160) (180) (4) ( ) ----- ----- ----- ----- ----- ----- -----
Division signal unit 250 220 40 (100) ----- ( ) ----- ----- ----- ----- ----- ----- -----
Infantry group headquarters 71 70 18 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- -----
3 infantry regiments, Each 3,843 11,529 9,000 2,130 6,393 (336) 324 108(72) ----- 18 18 12 ----- -----
Division field artillery regiment 2,300 2,000 (450) (1) ----- ----- ----- ----- ----- ----- ----- 36 -----
Division reconnaissance regiment 730 650 (188) (200) 28 16 4 ----- 4 ----- ----- ----- 7
Division Engineer regiment 900 750 (150) (700) (9) ----- ----- ----- ----- ----- ----- ----- -----
Division medical unit 900 750 (110) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- -----
4 field hospitals (operational 3) 1,000 690 ( ) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- -----
Division water purification unit 120 90 ( ) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- -----
Division transport regiment 1,800 1,400 (1,300) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- -----
Division ordnance unit 50 40 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- -----
Division veterinary unit 50 40 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- -----
Total 20,000 16,000 (7,500) (9,000) (382) (340) 112 (76) ----- 22 18 12 36 7


Alternatives:
Division mountain artillery regiment 3,400 ----- (1,400) (450) (1) ----- ----- ----- ----- ----- ----- 36 -----
Division cavalry regiment 950 900 (1,100) (500) 28 18 10 4 2 ----- ----- ----- -----
Infantry group tankette unit 100 ----- ----- ( ) ( ) ( ) ( ) ----- ----- ----- ----- ----- 10-17



NOTES:

1. Figures in parentheses are interpolations.
2. Parentheses only indicate presence but insuficient evidence is available to estimate a figure.
3. The figure of 72 heavy machine guns shown in brackets for the three infantry regiments assumes the presence of the 8-gun company.

Figure 15. Strength and weapons of standard division.





Units Personnel Horses Motor vehicles Rifles LMG Grenade
dischargers 		HMG Machine cannon
or 20mm anti-tank rifle 		37-mm or 47mm
antitank gun 		70-mm Battalion
guns 		75-mm Regtl guns 75-mm fld or mtn guns 105-mm
howitzers 		150-mm
howitzers 		Light Tanks Medium Tanks Tankette or
armored car
Division headquarters 465 66 23 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division signal unit 287 48 ( ) (120) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Infantry group headquarters 69 18 3 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Infantry group signal unit 114 24 ----- ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
3 infantry regiments, each 5,687 17,061 3,240 ----- 7,110 345 441 108 72 36 36 24 ----- ----- ----- ----- ----- -----
Artillery group headquarters 159 99 6 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Field artillery regiment 2,379 2,463 49 ( ) ( ) ----- ----- ----- ----- ----- ----- 12 24 ----- ----- ----- -----
Medium artillery battalion 951 769 ( ) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- 12 ----- ----- -----
Division reconnaissance regiment 730 188 61 260 28 16 4 ----- 4 ----- ----- ----- ----- ----- ----- ----- 7
Division tank unit 717 ----- 81 ( ) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- 20 48 -----
Division engineer regiment 1.012 116 12 (800) (9) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division medical unit 1,083 1,468 ----- ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
5 field hospitals 1,009 145 22 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division water purification unit 163 ----- 19 ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division transport regiment 2,729 1,222 176 ( ) (21) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- 6
Division ordnance unit 185 ----- 14 ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division veterinary unit 105 32 6 ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Chemical (decontamination) unit 190 ----- 30 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Total 29,408 9,906 502 (10,000) (405) (4567) 112 72 40 36 24 12 24 12 20 48 13


Alternatives:
Division mountain artillery regiment 3,420 1,835 ----- ( ) ( ) ----- ----- ----- ----- ----- ----- 24 12 ----- ----- ----- -----
Division cavalry regiment 950 1,100 ----- (500) 28 18 10 4 2 ----- ----- ----- ----- ----- ----- ----- -----
Infantry group tankette unit 100 ----- ----- ( ) ( ) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- 10-17




NOTES:
1. Figures in parentheses are interpolations.
2. Parentheses only indicate presence but insufficient evidence is available to estimate a figure,
3. This division is described as from Japanese sources.

Figure 16. Strength and weapons of "strengthened" division.



Units Personnel Horses Motor vehicles Rifles LMG Grenade
dischargers 		HMG Machine cannon
or 20mm anti-tank rifle 		37-mm or 47mm
antitank gun 		70-mm Battalion
guns 		75-mm Regtl guns 75-mm fld or mtn guns 105-mm
howitzers 		Tankette or
armored car
Division headquarters 415 217 (20) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- -----
Division signal unit 220 38 (20) (100) (4) ----- ----- ----- ----- ----- ----- ----- ----- -----
Infantry group headquarters 48 11 (5) ( ) (3) ----- ----- ----- ----- ----- ----- ----- ----- -----
Infantry group signal unit 14,493 2,268 ----- (7,110) (345) 441 108 72 18 36 12 ----- ----- -----
3 infantry regiments 160 94 (10) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- -----
Artillery group headquarters 2,315 1,834 (30) (400) ( ) ----- ----- ----- ----- ----- ----- 24 12 -----
Field artillery regiment 783 831 ----- (300) 25 12 6 6 ----- ----- ----- 24 12 -----
Division cavalry regiment 783 831 ----- (300) 25 12 6 6 ----- ----- ----- ----- ----- -----
Division engineer regiment 899 150 (15) (700) (9) ----- ----- ----- ----- ----- ----- ----- ----- -----
Division medical unit 995 117 (15) ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- -----
4 field hospitals 948 304 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division water purification unit 163 ----- (19) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division transport regiment 2,819 2,025 (135) (930) (24) ----- ----- ----- ----- ----- ----- ----- ----- (6)
Division ordnance unit 185 ----- (15) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Division veterinary unit 105 30 ( ) ( ) ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
Total 24,600 7,930 (284) (10,000) (411) 453 114 78 18 36 12 24 12 (6)

Alternatives:

Mountain artillery regiment 3,441 1,822 ----- ----- ----- ----- ----- ----- ----- ----- ----- 35 ----- -----




Figure 17. Strength and weapons of "strengthened" (modified) division.

NOTES:
1. Figured in parenthesis are interpolations.
2. Parentheses only indicate presence but insufficient evidence is available to estimate a figure,
3. This division is described as from the Japanese sources.



d. Identified Japanese divisions and their principal components.
(1) The following chart shows the identified divisions of the Japanese Army, their component units, the district from which they are conscripted, and the location of the depots from which they are supplied. Division signal and medical units, although included in the divisions, are not shown on the chart.

(2) The area from which an identified regiment is conscripted is the regimental conscription district. When the location of its depot differs from the headquarters of the conscription district, the depot location is shown in parentheses. The supporting units are conscripted from the whole divisional district. When the location of the depot differs from the headquarters of the divisional district, the depot location also is shown in parentheses.

As of May 1944
Num Divisions Regimental conscription district and/or location of depot Div inf regt Div cav or recon unit Div tank unit Div arty regt Div arty group Div engr regt Div inot regt
1 Gds ----- 1 Gds
2 Gds B 6 or
7 Gds 		1 Gds cav (Tokyo) ----- 1 Gds FA ----- 1 Gds 1 Gds
2 Gds Tokyo
(Tokyo)
(Tokyo)
(Tokyo)
3 Gds
4 Gds
5 Gds
2 Gd Recn (Tokyo) ----- 2 Gds FA of the arty group (Tokyo) Gds 2 Gds (Tokyo) 2 Gds (Tokyo)
1 Tokyo
Tokyo
Kofu
Chiba (Sakura)
1
49
57 		1 Reen Tokyo 1 1 FA of the arty group Tokyo 1 1 Tokyo 1 Tokyo
2 Sendai
Sendai
Niigata (Shibata)
Fukushima(Wakamatsu)
4
16
29 		2 Recon Sendai ----- 2 FA of the arty group Sendai 2 2 Sendai 2 Sendai
3 Nagoya
Nagoya
Shizuoka
Gifu
6
34
68 		3 Cav nagoya ----- 3 FA of the arty group Nagoya 3 3 Nagoya (Tokyo-hashi) 3 Nagoya
4 Osaka
Osaka
Osaka (Sakai)
Wakayama
8
37
61 		4 Reen Osaka ----- 4 FA Osaka (Shinoda-Yuma) ----- 4 Osaka (Takatsuki) 4 Osaka
5 Hiroshima
Hiroshima
Matsue (Hamada)
Yamaguchi
11
21
42 		5 Reen Hiroshima ----- 5 FA Hiroshima ----- 5 Hiroshima 5 Hiroshima
6 Kumamoto
Kumamoto
Miyazaki (Miyakonojo)
Kagoshima
13
23
45 		6 Cav Kumamoto ----- 6 FA Kumamoto ----- 6 Kumamoto 6 Kumamoto
7 Asahigawa
Hakodain (asahigawa)
Kushiro (Asahigawa)
Asahigawa
26
27
28 		7 Reen Asahigawa ----- 7 Mountain Asahigawa ----- 7 Asahigawa 7 Asahigawa
8 Hirosaki
Aomori
Akita
Aomori (Hikosaki)
5
17
31 		8 Reen Hirosaki 8 (Co) 8 FA of the Arty Group Hirosaki 8 8 Hirosaki (Morioka) 8 Hirosaki
9 Kanazawa
Kanazawa
Nagano? (Matsumoto)
Toyama
7
19
35 		9 Cav Kanazawa ----- 9 Mtn of the Arty Group Kanazawa 9 9 Kanazawa 9 Kanazawa
10 Himeji
Okayama
Kobe (Himeji)
10
39
63 		10 Reem Himeji ----- 10 FA of the Arty group Himeji 10 10 Himeji (Okayama) 10 Himeji
11 Zentsuji
Takamatsu (marugame)
Tokushima
Kochi
12
43
44 		11 Cav Zentsuji ----- 11 Mtn of the Arty group Zentsuji 11 11 Zentsuji 11 Zentsuji
12 Kurume
Fukuoka
Nagasaki (Omura)
Fukuoka (Kurume)
24
46
48 		12 Reem Kurume 12 24 FA of the Arty group Kurume 12 18 Kurume 18 Kurume
13 Sendai
Niigata (Shibata)
Fukushima (Wakamatsu)
Sendai
116
65
104 		13 Div Cav unit (Sendai) ----- 19 Mtn Sendai (Takata) ----- 13 Sendai 13 Sendai
14 Utsunomiya
Mito
Mnebashi (Takasaki)
Utsunomiya
2
15
59 		14 Reen Utsu ----- 20 FA Utsu ----- 14 Utsu (Mito) 14 Utsu
15 Nagoya? Kyoto Tsu 51
60
67 		----- 15 21 FA ----- 15 15
16 Kyoto
Kyoto
Kyoto (Fukuchiyama)
Tsu
9
20
33 		16 Reen Kyoto ----- 22 FA Kyoto ----- 16 Kyoto (Fushimi) 16 Kyoto
17 Himeji
Tottori
Okayama
Kobe (Himeji)
 53
54
81 		17 Inf group tkette Co ----- 23 FA Hineji ----- 17 Himeji (Okayama) 17 Himeji
18 Kurume
Nagasaki (Omura)
Fukuoka (Kurume)
Fukuoka (Kokura)
55
56 B 114 		22 Cav Bn? ----- 18 Mtn Kurume ----- 12 Kurume 12 Kurume
19 Ranan
(Ranan)
(Kainei)
(Ranan)
73
75
76 		19 Reem ----- 25 Mtn of the Arty Group (Ranan) 19 19 (Kainei) 19 (Ranan)
20 Keijo
78 BR> 79
80 		20 Reen (Ryuzan) ----- 26 FA of the Arty group (Ryuzan) 20 20 (Ryuzan) 20 (Ryuzan)
21 Kanazawa ----- 62
82
83 		21 Div Tkette Co ----- 51 Mountain ----- 21 21
22 Utsunomiya Kanasawa?
Mito
Maebashi (Takasaki)
Nagano (Matsumoto)
84
85
86 		22 Inf group Tkette co Utsu ----- 52 Mountain Utsu ----- 22 Mito? 22 Utsu
23 ----- ----- 64
71
72 		23 Reen 23 13 FA of the Arty group 23 23 23
24 Zentsuji, Hirosaki
Matsuyama
Yamagata
22
32
89 		24 Reen ----- 42 FA of the Arty group 24 24 24
25 Osaka, Himeji, Kurume
Fukuoka (Kokura)
Tottori
Wakayama?
14
40
70 		75 cav ----- 15 Mtn of the Arty group 25 25 25
26 Nagoya?
Nagoya
Gifu
Shizuoka
Ind 12
Ind 13
Ind 		26 Reen ----- 11 Ind FA Nagoya? ---- 26 26






7. DIVISION HEADQUARTERS.


a. General.
A division is commanded by a lieutenant general, with a colonel of the General Staff as Chief of Staff. The staff is in two sections - The General Staff section and the administrative section. To the staff are attached five departmental sections (See d below) and ordnance, a signal and a veterenary detachment. In all, there are about 300 officers and enlisted men.


Figure 18 		b. General Staff Section.
(1) The general staff section is composed of about 75 officers and enlisted men. The Chief of Staff supervises and coordinates the work of the Genral and Administrative staffs. He acts as the link between the division commander and the unit commanders, heads of departments, and the civil autorities. All questions are referred to the Chief of staff before submission to the division commander either by heads of departments or by the group or regimental commanders.

(2) G-1 is a lieutenant colonel who deals with operations, communications, and training. He has a signal officer, a code officer, a gas officer and an ordnance officer as assistant.

(3) G-2 is a major who deals primarily with intelligence, maps, censorship, and mobilization.

(4) G-3 is a captain who deals with rear services, supplies, and line-of-communication matters.

(5) The adjutant is a lieutenant colonel who is assisted by a captain and liutenant.

c. Administrative staff section. This section, together with the departmental sections, is composed of about 175 officers and enlisted men. The head of the section is a lieutenant colonel who deals with all reports, except those relating to operations, and exercises general supervision of administrative work. The section includes a captain or lieutenant in charge of promotions, appointments, personal records of officers and noncommissioned officers, personnel, and administrative details of mobilisation; a captain or lieutenant in charge of all affairs connected with the departmental services, and who is responsible for administrative orders; and a captain or lieutenant in charge of documents and the secretarial work of the division.





d. Depatmental section. the number of officers employed in each special staff section varies with divisions. The services represented are as follows:

(1) Intendance. A colonel, three field officers, and seven or more capatins or lieutenants.

(2) Medical. A colonel and two or three other medical officers.

(3) Veterenary. A lieutenant colonel and one or two other veterinary officers.

(4) Ordnance. One field officer and two or more captains or lieutenants from the technical service.

(5) Judicial (legal). Several officers.

e. Detachments. The ordnance, signal, veterenary, and guard detachments, together with the drivers of vehicles used to transport the division staff and part of its equipment, make up the rest of the headquarters.