CHAPTER 3 - WWII JAPANESE FIELD ORGANIZATIONS - SECTION 3



TABLE OF CONTENTS








11. DIVISION ARTILLERY.



a. General.
The normal artillery component of a standard division is a 36 gun regiment of 75-mm field or mountain artillery which may be motorized, horse drawn, or pack.

b. Field artillery regiment (horse drawn).
(1) General.
The regular field artilleryu regiments of a regimental headquarters, three battalions of 75-mm guns (each battalion having a battalion headquarters, three gun companies, and a train); and a regimental train. Total strength is about 2,300 officers and enlisted men. Normal armamament is thirty six 75-mm guns.



(2) Organization.

(3) The regimental headquarters. The regimental headquarters consists of a colonel or lieutenant colonel in command, an adjutant, and a staff of about 14 noncommissioned officers and enlisted men. There is a headquarters operational group composed of an observation platoon, and a signal platoon consisting of one wire (line or L/T) section and one radio section. The total strength of the headquarters including the headquarters operational group, is about 120 officers and enlisted men.

(4) The regimental train is commanded by a captain or lieutenant and is divided into the 3 ammunition platoons and a field (baggage) platoon. The total strength is about 140 officers and enlisted men.

(5) A battalion consists of a headquarters, 3 companies, and a train. The strength is about 680 to 700 officers and enlisted men.

(6) Battalion headquarters, commanded by a major, is considered a battalion staff and a headquarters operational group. The latter is divided into an observation platoon and a signal platoon. A machine gun section for defense also is reported. The total strength of the headquarters including the ehadquarters operational group, is about 80 officers and enlisted men.

(7) The battalion train is commanded by a captain or lieutenant and consists of 3 ammunition sections and a field (or baggage) section. The total strength is about 60 officers and enlisted men.

(8) Companies commanded by captains, are composed of a company staff, a headquarters operational group, 2 gun platoons (each of 2 sections of about 20 men each), and a company train. The total strength is about 180 officers and enlisted men, with four 75-mm field guns.


(9) Regimental equipment. there is a total of thirty six 75-mm field guns. It is estimated that there are 450 rifles (138 per battalion and 34 per company) and approximately 2,000 horses to the regiment.

(10) Should the artillery regiment be fully motorized the following estimates are likely:

Regimental headquarters 124 personnel
Regimental train 107 personnel
Three battalions (each 563) 1689 personnel
Total regimental strength 1920 personnel




c. Mountain artillery (pack)

(1) General.
Mountain artilleryregiments are similar to field artillery regiments except that all equipment is carried on pack animals, and the companies are armed with 75-mm mountain guns instead of 75-mm field pieces. Strengths are increased so that the regimental totals are about 3,000 to 3,400 officers and men with thirty six 75-mm mountain guns. Some mountain artillery regiments may include a battalion of 105-mm pack (mountain) howitzers. Existence of such a weapon has been reported but not confirmed.

(2) Organization.

Figure 41. WWII Japanese Mountain Artillery Regiment Organizational Chart.
(3) Strength analysis (estimates only).
(a) Regimental headquarters. - 150 men.

1. Administrative section - 15 men.

2. Headquarters operational group. - 135 men.

Observation platoon 60
Wire (L/T) section 50
Radio (W/T) section 25




(b) Regimental train. - 310 men.

(c) Three battalions (each 980). - 2,940 men,

1 Battalion headquarters.
100 men.
----------------

Administrative section ---------- 10
Headquarters operational group ---------- 90


2
Battalion train.

234 men.
3 Three gun companies (each 212).
212 men.
----------------

Company headquarters -------- 60
Company train -------- 42
2 gun platoons (each 55) -------- 110



(4) Regimental equipment. There is a total of thirty six 75-mm mountain guns.

d. Mixed field artillery regiment.
(1) General.
The field artillery regiment normally consists of a headquarters and train 3 battalions of 75-mm field guns or 105-mm howitzers. When horse drawn , the regiment members numbers approximately 2,380 officers and enlsted men. This figure decrease with the degree of motorization.

(2) Organization.


Figure 42. WWII Japanese Mixed Field Artillery Regiment Organizational Chart.
e. The medium battalion. This battalion consists of a headquarters (divided into an administrative staff and a headquarters operational group) and 3 companies of four 150-mm howitzers. Its total personnel strength is about 950, and there are 769 horses.

f. Artillery in the strengthened diisions.
(1) The artillery element in strengthened divisions consists of an artillery group, composed of the artillery group headquarters, a regiment of field artillery containing 75-mm and 105-mm weapons, and a medium artillery battalion of 15o-mm howitzers. Other independent artillery and antiaircraft units may be assigned or attached. The artillery group is under command of either a major general or a colonel.

(3) Equipment. There is a total of twelve 75-mm field guns and twenty four 105-mm howitzers.

(2) Artillery group headquarters. An artillery group headquarters consists of approximately 160 officers and enlisted men. It includes a staff, a small guard, and a train, and an observation-balloon platoon also may be included. The functions of the group headquarters are to command the organic artillery of the division and unify control of attached artillery.



12. DIVISION CAVALRY.



a. General.
Each infantry division normally contains either one cavalry or one reconnaissance regiment or unit. Within both the standard and the strengthened divisions, the regimental cavalry is organized basically along the same lines. However, within the modified strengthened division there is a marked difference of organization; accordingly, a separate detailed organization has been shown for the modified cavalry regiment. Also within this division, unlike the other two, there does not appear to be a reconnaissance regiment as an alternative for the cavalry regiment.

b. The cavalry regiment.
(1) General.
The division cavalry regiment conists of a headquarters and train, 3 rifle and sabe companies, and a machine gun company. The total strength is 950 officers and enlisted men.

(2) Organization.

Figure 43. WWII Japanese Cavalry Regiment Organizational Chart.


(3) Equipment (estimate only).

Regimental Headquarters Rifle and Saber Company Machine Gun Company Regimental Totals
Rifles or carbines 200 100 ----- 500
Light Machine Guns 1 9 ----- 28
Grenade Dischargers ----- 6 ----- 18
Heavy machine Guns (7.7-mm) ----- 2 4 10
20-mm AT Rifle ----- ----- 4 4
37-mm AT Gun ----- ----- 2 2
Horses 380 180 180 1,100



Figure 44. WWII Japanese Cavalry Regiment Weapons and Equipment.


(4) Strength analysis

(a) Regimental headquarters. - 82 men.

Command section 20
Signal section (mainly radio) 50
Equipment section 12


(b) Regimental train. - 200 men.

(c) Three rifle and saber companies. (each 170) - Total 510.

Company commander 1
Company headquarter 16


(d) Three rifle and saber platoons (each 43) - Total 129.

- Platton commander.
- Liaison noncommissioned officer.
- 3 light machine gun sections (noncommissioned officer and 10 men).
- 1 grenade dischrager section (noncommissioned officer and 7 men).
- 2 grenade dischargers


(e) One machine gun platoon. - 24 men,

- Platoon commander.
- Liaison noncommissioned officer.
- Two machine gun sections (noncommissioned officer and 10 men).


(f) Machine gun company. - 158 men,
Company commander 1
Company headquarters 13


1. Two machine gun platoons (each 46)
Platoon commander.
Liaison noncommissioned officer.
2 machine gun sections (noncommissioned officer and 10 men).
Two 20-mm antitank rifle sections (noncommissioned officer and 10 men).


2. One antitank gun platoon (37-mm) - 27 men.
Platoon commander.
Observer section.
Two gun sections (noncommissioned officers and 10 men).


3. Ammunition platoon - 25 men.
Platoon commander.
3 sections of 8 men.




c. Cavalry regiment (modified organization).

(1) General.
The cavalry regiments consists of a headquarters, 2 rifle and saber companies, and a machine gun company. Total strength is about 785 officers and men.

(2) Organization.


Figure 45. WWII Japanese Cavalry Regiment Organizational Chart.

(3) Equipment (estimates only).

Regimental Headquarters Rifle and Saber Company Machine Gun Company Regimental Totals
Rifles or carbines 100 100 ----- 300
Light Machine Guns 1 12 ----- 25
Grenade Dischargers ----- 6 ----- 12
Heavy machine Guns (7.7-mm) ----- ----- 6 6
20-mm AT Rifle ----- ----- 6 6
Horses 349 191 200 831






Figure 46. Equipment.




(1) General.

Reconnaissance units are divisional cavalry troops and may be used as an alternative to a cavalry regiment. The reconnaissence regiment consists of a headquarters, 1 cavalry company, 2 motornorne companies, 1 armored car (or tankette) company,and 1 motor truck company. The total strength is about 730 officers and enlisted men.

(2) Organization.


Figure 47. WWII Japanese Reconnaissance Regiment Organizational Chart.


DESCRIPTION STRENGTH
Rifles or carbines 260
Light machine guns 28
Heavy machine guns 4
37-mm or 47-mm antitank guns 4
Grenade dischargers 16
Light armored cards or tankettes 7
Other vehicles 61
Horses 188
TOTAL ASSETS / EQUIPMENT 568




13. DIVISION TANK UNIT.


a. General.
Only the strengthened divisions contain an organic tank unit equipped with light and medium tanks. The majority of Japanese divisions however, will be found to have tankettes, either in the infantry group tankette company or in the reconnaissance regiment. Division tank units are believed to have about 20 light tanks and 48 medium tanks, with some of these held in reserve within the combat train. The unit conists of a headquarters, one light tank company, two medium tank companies, and a combat train. There are about 80 trucks included in the train.

b. Organization.


Figure 48. WWII Japanese tank division organizational chart.


c. Strength analysis.

Headquarters 100
Light tank company 86
2 medium tank companies (each 141) 282
Combat train 250
Tank Unit - Total 718
d. Equipment.

Light tanks 20
Medium tanks 48
Trucks 80




14. ENGINEERS



(1) a. General.
The engineer regiment of a division is normally composed of a headquarters, three companies, and a regimental material platoon. The total strength is 900 to 1,000 men. Division engineers include among their personnel men trained in tank trap construction, demolition work, and small river crossing operations. The 3 companies of the regiment do not specialize in one particular aspect of engineering, but are designed for sub-allotment, one to each infantry regiment, to fulfill their ordinary engineer requirements.

If extensive engineer tasks, such as large scale bridging operations, have to be carried out, specialized engineer units are attached for the purpose.

(2) b. Organization.


Figure 49. WWII Japanese Army Engineers Organizational Chart.
(3) Regimental headquarters consists of a colonel or lieutenant colonel in command and 4 to 6 other officers; it has a total of approximately 100 offiers and enlisted men. It is divided into various sections charged with signal, medical intendance, ordnance and supply duties. The men are armed with rifles, and it is estimated that the armament of the regiment includes 6 of each of light machine guns, grenade dischargers, mortars, and flame throwers.

(4) Companies are commanded by captains or first lieutenants, 4 platoons and a material station. The headquarters is believed to total about 25 men. Platoons usually are commanded by second lieutenants and are divided into 4 sections each. A platoon consists of about 50 men. The material section carries tool and oher equipment, with pack and draft sections; its strength is about 25 men. The total company strength is about 250 men. (5) The regimental material platoon comprises a headquarters and 2 sections, with a total of 50 to 100 men. Equipment may include 15 motor trucks and various construction implements.

b. Two company regiments.
Some divisions may have two-company engineer regiments. The company consists of a headquarters, 4 platoons, and a material section; its total length is about 240 men with 20 horses. Included as well, is a regimental headquarters and a material platoon, bringing the strength of teh regiment to about 600 men.


c. Engineer units.
These are few in number; They sometimes appear as components of the small sized, special type divisions. The commanding officer is a captain. Little information has been received to indicate the numerical strength and composition of such units, but it has been reported to cosist of a headquarters and 3 platoons of 4 sections each.

15. MEDICAL


a. General.
The Japanese division medical service is an extensive one and includes a medical unit. In addition, other components of the division include a number of medically trained personnel. A reason for this extensive organization is probably the Japanese principle ofkeeping their casualties as far forward as possible in order to facilitate their quick return to fighting units. Another factor which the Japanese may consider a compensation for the size of their medical organization is that a large proportion of the personnel in medical units are reported to be armed, and instances of their employment as fighting troops are known.

b. Organization.


Figure 50. Medical Service Division Organizational Chart.
c. Medical unit
The medical unit consists of a headquarters and train and 3 collecting companies of 3 stretcher platoons and 1 ambulance platoon each. The medical unit, with a personnel strength of 700 to 1,000, is equipped with about 180 litters and 45 ambulances. The collecting companies each have about 20 litters and 15 ambulances. Headquarters train has additional carts for loading medical supplies and patients' clothing, as well as for chemical warfare decontamination material.





d. Field hospitals
(1) General.
Each field hospital, with its required train, has a personnel of about 250 and is organized to accomodate 500 patients. It may be motorized, pack, or draft. The medical personnel of the field hospitals is under direction of the chief medical officer of the division. although divisions are known to have 4, and sometimes 5, field hospitals in their' organization, only 3 are usually identified as active in combat zones.The fourth sometimes called the field reserve hospital, has been identified functioning as a convalescent and evacuation station on the line of communications.

(2) Organization.

Figure 51. WWII Japanese Field Hospital Organizational Chart.
e. Water purification unit
These units normally have a personnel strength of 50 to 150. They are equipped with material for supply and purification of water for the division, and are charged with prevention of infectious deseases.

f. Medical personnel in division units.
Medical officers are attached to units of all arms on the approximate scale of three per battalion or equivalent unit. In addition, the battalion medical officer usually assisted by two medical service noncommissioned officers, while medical service orderlies are attached to subunits on an average of one to platoon.

16. TRANSPORT


a. General.
The transport regiment ha stwo battalions which may be draft, pack or motorized. Regimental strength varies between 1,800 and 2,800. About one third of the personnel may be equipped with rifles.

Organization.
(1) A standard division transport regiment is believed to be composed of: a headquarters, one motor battalion and one draft battalion. The draft batallion will be made up of three or four companies, with each company divided into three transport platoons , each of which in turn is divided three sections. The motor battalion is believed to be made up of headquarters and two or three truck companies, each of three platoons, with each platoon divided into three sections.

(2) Each truck company is estimated at 150 men. Some motor battalions may include a road maintenance company of 125, and an armor car transport company of 50 men. These units are in addition to the truck companies, which ha sabout 50 vehicles. Truck capacity is about 1 1/2 tons. The draft company has 250 single-horse, 2-wheeled, transportation carts, each with a capacity of 400 to 500 pounds.


(3) Evidence is available that a division transport regiment also could be composed of a headquarters, 8 draft companies and a veterinary detachment. Each of the draft companies approximates 350 officers and enlisted men and is divided into 3 transport platoons and a combat platoon. Two pack-horse companies may be substituted for one draft company. A pack horse company, consisting of approximately 450 officers and men, is similar in organization to the draft company. It has about 300 pack horses, each with an average loading capacity of 200 pounds.

(4) In an eight-company draft regiment typical supply columns are loaded as follows:

I Small arms ammunition, 1 company and 1 platoon
II Artillery ammunition 2 companies and 1 platoon
III Chemical warfare 1 platoon
IV Rations and forage 4 companies




17. VETERINARY UNIT


Each division has as part of its organization a veterinary unit of from 50 to 100 officers and enlisted men. It probably consists of veterinary hospital staff with individual sections assigned during combat to the various divisional units.

18. ORDNANCE UNIT


Division also have ordenance personnel assigned from the technical service. The unit consists of 50 to 200 officers and enlisted men depending on the size of the division.

19. CHEMICAL WARFARE UNIT


a.
Available evidence (1944) indicates that only the strongest dicisions have an organic decontamination unit. Such a unit divided into three platoons, each of three sections and a unit train. The first two platoons which are apparently similar in organization, have a number of armored transport vehicles and trailers for decontaminated roads and other areas. The third platoon has decontamination cars for handling contaminated clothing and equipment, while the three-section wagon train carries the necessary equipment and reserve clothing.

b.
he decontamination unit may be either motorized or pack; basic organizations of each type are similar. If motorized the unit's total strength approximates 150; a pack unit will have a personnel of about 250.

c.
No gas or decontamination units are known to exist in other typw divisions. However, picked personnel in all units have been designated as "gas personnel" and are responsible for decontamination in addition to their regular duties. This personnel also can be formed into special "smoke" companies for the laying of smoke screens and it is probable that in some cases they are capable of handling chemical warfare agents as well.

20. TANK GROUPS (ARMORED DIVISIONS)


a. General.
A number of reports have been received of the existence of tank groups ( Senshadan). These are believed to consists of 3 or 4 tank regiments plus a signal and engineer unit. (for the organization of a tank regiment, see Section II. Par. 3a (1) ). Other evidence indicates that the Japanese may have formed amored divisions, of which the tank groups may be the nucleus.

b. Oragnization.
Organization of such an armored division has been described as follows:

NUM WWII JAPANESE ARMORED DIVISION PERSONNEL VEHICLES
1 Headquarters 200 30
2 Infantry unit, motorizrd 3,800 475
3 3 tank regiments (about 250 tanks) 2,550 640
Eight 105-mm guns
Four 155-mm howitzers
4 Antitank unit (eighteen 47-mm A/T) 500 70
5 Antiaircraft unit (four 75-mm) 175 25
6 A/A Machine-gun unit (Sixteen 20-mm) 300 50
7 Engineer unit 500 60
8 Transport unit 1,500 350
9 Medical Unit 285 50
-------- --------
TOTAL 10,500 1,850




21. GROUPS, BRIGADES, AND OTHER ORGANIZATIONS.


a. General.
The Japanese have several varieties of organizations, all of which have been designed to fit particular operational consitions and requirements.

b. Cavalry groups and cavalry brigades.
(1) General
Japanese cavalry groups consit of two cavalry brigades, signal units, and trains.

(2) Organization of cavalry brigade.


Figure 52. Organization of the Cavalry Brigades.
(3) Antiaircraft and antitank units have also been reported as forming part of these brigades. The total strength of the cavalry brigade has been reported to be about 5,000 to 6,000.

c. Independent infantry groups.
The normal infantry group is sometimes found to be independent - that is, it has three infantry regiments without supporting arms and services.



d. Independent infantry brigade.
In addition to the infantry brigades assigned to the "special" division (see figure 14) the Japanese have a number of independent infantry brigades. These brigades consist of four independent infantry battalions and signal unit. Their estimated strength is 4,900.

e. Independent mixed brigades.

(1) General.

The Japanese independent mixed brigades, as they were formed in China in 1937-1938 for garrison and antiguerrilla duties, are beliened to be organized as follows:

Figure 53. Independent mixed Brigades.
The battalions consist of 3 or 4 companies, an their strength has been reported to be about 700 to 900 men. Other units are thought to be comparatively small. The total strength of these brigades has been variously reported at between 6,000 to 10,000 men. Several of these independent mixed brigades recently have been converted into infantry divisions, and it is believed that this process of conversion still may be in operation.


(2) Independent mixed brigades (motorized).
At about the time of the outbreak of WWII the Japanese began to form independent mixed brigades for a different purpose from those which existed in China. These brigades were shock troops and included tanks, antiaircraft guns, and medium artillery. The infantry element was an infantry regiment of three battalions each of four companies. at least one of these brigades is known to have been motorized. Its organization followed:


Figure 54. Motorized independent mixed brigade.


f. Amphibious brigades.

(1) General.
A new type of unit has recently (1944) made its appearance. It is composed of a headquarters and 3 battalions and its strength is about 3,200. A battalion described by the Japanese follows:

(2) Organization.


Figure 55. WWII Japanese rifle company Organizational Chart.
The rifle companies were composed of three rifle platoons, of five sections each, a trench mortar platoon, ans a heavy weapons platoon. The trench mortar company consisted of three platoons of four sections each. While the gun company had three mountain and antitank guns. The 1st Amphibious Brigade had supporting artillery tank, engineer, machine cannon, and signal units directly under brigade headquarters, bringing total personnel strength to about 4,000. The brigade was commanded by a major general.