Technical Manual, U.S. War Department, October 1, 1944
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Chapter III: Field Organization
Section I: Major Organizations
Note. In some cases in this chapter, sufficiently definite and comprehensive information has not been available to enable representatives of the participating headquarters to reach fully 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 he considered the equivalent of the command of a 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 should 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 strength of about 130,000, but its actual strength was always greatly below this figure because of attrition en route, casualties, and detachments. It included the following units:
5. ARMY CORPS. Japanese military 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 signal unit.
Infantry group headquarters and 3 infantry regiments.
Cavalry regiment or reconnaissance regiment.
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; and C, the special. Consequently, the strength and classification of their divisions are largely dependent 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 operational areas. It is composed of organic elements listed in paragraph a 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 unit for 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 the 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 weapons 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.
d. Identified Japanese divisions and their principal components. (1) The following chart shows the identified divisions of the Japanese Army, their component units, the districts 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.
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 an ordnance, a signal, and a veterinary detachment. In all, there are about 300 officers and enlisted men.
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 General and Administrative Staffs. He acts as the link between the division commander and the unit commanders, heads of departments, and the civil authorities. 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 assistants.
(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-communications matters.
(5) The adjutant is a lieutenant colonel who is assisted by a captain and a lieutenant.
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 mobilization; 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. Departmental sections. 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 captains or lieutenants.
(2) Medical. A colonel and two or three other medical officers.
(3) Veterinary. 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, veterinary, 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.
8. DIVISION SIGNAL UNIT. a. General. The division signal unit, commanded by a captain, is composed of a headquarters, two wire (line or L/T) platoons, one radio (wireless or W/T) platoon, and a material (equipment) platoon. Its strength is about 250 officers and enlisted men.
(1) Variations in the strengths of this unit as shown in the different divisions may be explained by the varying number of radio sections. In all signal units it is common practice to add or decrease the number of radios as required.
(2) The company headquarters consists of a command section composed of the captain in command and about 20 noncommissioned officers and enlisted men. A runner or liaison section may be included.
(3) Each wire (line or L/T) platoon is divided into four sections. Total strength of the platoon is about 50 officers and enlisted men. A first or second lieutenant is in command. The radio (wireless or W/T) platoon is divided into sections each with one set. The number of sections varies from about 8 to 12. Total strength is about 100 to 125 men. A first or second lieutenant is in command.
The material (equipment) platoon is divided into two equipment sections. Total strength is about 35.
c. Equipment. The approximate total of signal equipment in the unit is 32 telephones, 30 miles of insulated wire. 2 radio sets (ground to air), and 8 to 10 other radios. The unit also utilizes pigeons, dogs, helio lamps, semaphores, and ground panels, as well as plane pickups. Some personnel are armed with rifles.
9. THE INFANTRY GROUP. a. General. The infantry group is commanded by a major general and consists of a headquarters, an infantry group signal unit (only in the strengthened division), and three infantry regiments. In some instances, tankette companies, of 80 to 120 men with 10 to 17 tankettes, have been assigned to the infantry group.
b. Infantry group headquarters. The headquarters, composed of 70 to 100 officers and men, is divided into an administrative staff, a headquarters guard (equipped with automatic weapons), and a small field (baggage) section. In the standard division a small signal unit may be furnished from the division signal unit.
c. Infantry group signal unit. Found only in the strengthened divisions, this unit usually is commanded by a captain and is divided into a company headquarters, a wire (line or L/T) platoon, and a radio (wireless or W/T) platoon. The strength is about 115 officers and enlisted men.
d. Infantry group tankette company. These units have been identified in a few divisions. They are believed to be organized into three or four platoons and a company train, with a total of from 80 to 120 personnel. They are believed to have 10 to 17 tankettes and trailers. They probably are used for reconnaissance purposes, since divisions in which they are found normally do not have cavalry or reconnaissance regiments. They also may be used for front-line transport.
10. THE INFANTRY REGIMENT. a. General. The regiment is commanded by a colonel and its components are, in general:
Regimental headquarters (including regimental train).
Regimental signal company.
Regimental infantry gun unit.
Regimental antitank gun company.
3 infantry battalions.
A pioneer or labor unit may be added.
b. Tabular strength and equipment tables. The following tables illustrate the two types of the strengthened regiment, as described by the Japanese. The first table illustrates a substantially stronger infantry regiment in which a heavy weapons platoon has been added to the rifle companies and more infantry guns have been added to the regiment.
c. Infantry regimental headquarters. (1) General. The infantry regimental headquarters normally is composed of about 55 officers and enlisted men. It consists of a staff, made up of administration, code and intelligence, ordnance, and intendance sections. In addition there is an antiaircraft section, or headquarters guard, and a color guard. Total strength of headquarters with train is about 176 officers and enlisted men.
(2) Strength analysis. (a) Officer personnel.
(b) Administration section.
(c) Code and Intelligence section. Two noncommissioned officers and eight men.
(d) Ordnance section. One ordnance noncommissioned officer and six technical noncommissioned officers.
(e) Intendance section. Three men, including pay noncommissioned officer.
(f) Antiaircraft section or headquarters guard (1 light machine gun). One noncommissioned officer and four men.
(g) Color guard. Five men.
(3) Regimental train. (a) General. The regimental train is divided into a field (baggage) section and an ammunition section. The baggage section usually includes about 30 one-horse, two-wheeled transportation carts, or about 40 pack horses. It carries the regimental baggage as well as one day's rations for regimental units not included in battalions. Kitchen equipment normally is carried in the division train, but it may be attached to regiments. Frequently all trains of all regimental units are grouped in one body. The ammunition train, equipped with horses and two-wheeled transport carts, carries a day's unit of fire for the regiment.
(b) Strength analysis.
1. Field (baggage) section. One noncommissioned officer and 39 men.
2. Ammunition section. One noncommissioned officer and 80 men.
3. Regimental train. 121 men.
(c) Size of the regimental train will vary. If motorized, the train will be reduced in most cases.
d. Regimental pioneer (labor) unit. The type "A" organization definitely includes in its establishment a regimental pioneer unit of set composition. This consists of a commander, 6 sections, and a material section. It numbers from 100 to 200 men, and its duties consist of general construction work. When "B" class divisions are moved into areas where personnel are required for demolition work, road construction, etc., a labor unit, consisting of four or five sections, can be drawn from the infantry companies and augmented by a few engineers. While a regimental labor company, with a strength as high as 250, may be found in any division, this does not necessarily involve any increase in the strength of the regiments.
e. Regimental signal company. (1) General. The signal company consists of a headquarters, one wire (line or L/T) platoon, and one radio (wireless or W/T) platoon, with a total of about 132 officers and men.
The number of radio sets used in comparison with the number L/T sets will depend on the type of operations involved.
(3) Strength analysis. (a) Company commander—captain or first lieutenant.
(b) Company headquarters (command section). Twenty-nine men.
1. Administration section.
2. Runner (liaison) section. Warrant officer in charge and 18 men.
(c) No. 1 Platoon (Wire or L/T). Twenty-nine men.
4 wire sections (noncommissioned officer and 6 men per section).
(d) No. 2 Platoon (radio or W/T). Seventy-three officers and men.
8 Radio sections (noncommissioned officer and 8 men per section).
(4) Equipment. The approximate signal equipment in the company is 12 to 20 telephone sets, 11 to 30 miles of insulated wire, 3 to 5 light radio sets, 2 to 3 ground to air sets, ground to air panels, dog sections, pigeons sections, heliograph, and other usual signal equipment.
f. Regimental infantry gun company. (1) General. The company consists of a headquarters, a firing unit of 2 platoons (total of 4 guns), and an ammunition platoon. The total strength is 122 officers and enlisted men.
(3) Strength analysis. (a) Company commander. Captain.
(b) Ordnance officer. Captain.
(c) Company headquarters (command section). Twenty-three men.
1. Administration section.
2. Signal section. Noncommissioned officer and six men.
3. Observation section. Noncommissioned officer and four men.
(d) Firing unit (two gun platoons, each thirty-three). Nos. 1 and 2 gun platoons.
2 gun sections (noncommissioned officer and 15 men per section).
(e) Ammunition platoon. 31 men.
(f) Regimental infantry gun company. Total—122 men.
(5) The armament of the regimental gun company often has been found to consist of two regimental guns and two antitank guns, instead of the standard four 75-mm regimental infantry guns. At times mortars (probably the short barreled 81-mm) may be substituted or included.
g. Regimental infantry gun battalion. (1) General. The battalion consists of a small headquarters group of 24 officers and enlisted men and 2 "A" type gun companies. The company comprises a firing unit of 2 platoons (total of four guns) and an ammunition platoon. The strength of the company is 170, and the total strength of the battalion is 364 officers and enlisted men.
(3) Strength analysis of "A" type gun company. (a) Company commander. Major or captain.
(b) Ordnance officer. Captain.
(c) Company Headquarters (command section). Twenty-seven men.
1. Administration section.
2. Signal section. Noncommissioned officer and six men.
3. Observation section. Noncommissioned officer and 10 men.
(d) Firing unit (two gun platoons, each fifty-five). Nos. 1 and 2 gun platoons.
(e) Ammunition platoon. 31 men.
(4) Equipment. Four 75-mm regimental infantry guns.
h. Regimental antitank company. (1) General. The regimental antitank company consists of a headquarters, a firing unit of three platoons, and an ammunition platoon. The total strength is about 115 officers and enlisted men equipped with six antitank guns.
(3) Strength analysis. (a) Company commander—Captain.
(b) Company headquarters (command section). Nineteen men.
1. Administration section.
2. Observation section. Noncommissioned officer and six men.
(c) Firing unit (three gun platoons, each 25). No. 1 gun platoon (Nos. 2 and 3 platoons the same).
(d) Ammunition platoon. 21 men.
(4) Equipment. Six 37-mm antitank guns.
(5) A common variant is for this unit to be merged with the regimental infantry gun unit, the armament of which then consists of 2 regimental guns and 2 antitank guns.
(6) The "A" type antitank gun company has increased strength of about 130 officers and enlisted men and is equipped with six 37-mm antitank guns. In the strengthened type division the antitank company is not a regimental unit, but there are 3 antitank companies, one in each infantry battalion, and each company usually is equipped with 4 antitank guns. The strength of this 4-gun company is approximately 100 officers and enlisted men.
i. Infantry battalion (standard). (1) General. The infantry battalion normally is commanded by a major and consists of a headquarters and train, 4 rifle companies, and machine gun company, and a battalion gun platoon. Its total strength is 1,100 officers and enlisted men.
(3) Equipment. There are approximately 677 rifles, 36 grenade dischargers, 37 light machine guns, 12 (8) heavy machine guns (7.7mm), 2 battalion 70-mm guns.
j. Infantry battalion (strengthened). (1) General. This infantry battalion normally is commanded by a major and consists of a headquarters and train, 4 rifle companies, a machine gun company, a battalion gun company, and a battalion antitank company. Its total strength is 1,626 officers and enlisted men.
(3) Equipment. There are approximately 730 rifles, 37 light machine guns, 49 grenade dischargers, 4 heavy machine guns (7.7-mm), eight 20-mm antitank rifles, four 37-mm antitank guns, 4 battalion 70-mm guns.
k. Infantry battalion (strengthened, modified). (1) General. This infantry battalion normally is commanded by a major and consists of a headquarters and train, 4 rifle companies, a machine-gun company, and a battalion-gun company. Its total strength is 1,401 officers and enlisted men.
(3) Equipment. There are approximately 750 rifles, 37 light machine guns, 49 grenade dischargers, 12 heavy machine guns (7.7-mm), eight 20-mm antitank rifles, and four 70-mm battalion guns.
l. Battalion headquarters. (1) General. The battalion headquarters normally consists of about 37 officers and enlisted men, divided into administration, ordnance and intendance, liaison, code and intelligence, and an antiaircraft, or headquarters guard, sections. In addition there is a battalion train. Total strength of battalion headquarters and train is 147 officers and enlisted men.
(2) Strength analysis.
(a) Officer personnel. 8 men.
(b) Administration section. 14 men.
(c) Ordnance and intendance section. Two noncommissioned officers and one technician.
(d) Liaison section. 4 men.
(e) Code and intelligence section. One noncommissioned officer and two men.
(f) AA section or headquarters guard (1 LMG). 5 men.
(3) Battalion train. The battalion train is generally similar in equipment and function to the regimental train.
(a) Field (baggage) section. Noncommissioned officer and 49 men.
(b) Ammunition section. Noncommissioned officer and 59 men.
(c) Battalion train. 110 men.
Note. Strength of the battalion train may vary. If motor transport is used it will normally be reduced.
m. Infantry rifle company ("B") type. (1) General. The company consists of a company commander, usually a captain, a company headquarters, and three rifle platoons. Total strength is 181 officers and enlisted men.
(3) Strength analysis. (a) Company commander. Captain.
(b) Company headquarters (command section).
(c) 3 Rifle platoons (each 54). 162 officers and men.
1. No. 1 platoon.
2. No. 2 and No. 3 platoons. Same as No. 1.
(4) Equipment. There are in the company 139 rifles, nine light machine guns, and nine grenade dischargers.
n. Infantry rifle company ("A" type without heavy weapons platoon). (1) General. The company consists of a company commander, usually a captain, a company headquarters, and 3 rifle platoons. Total strength is 205 officers and enlisted men.
(3) Strength analysis. (a) Company commander. Captain or First Lieutenant.
(b) Company headquarters (command section). 18 men.
(c) 3 Rifle platoons (each 62). 186 officers and men.
1. No. 1 Rifle platoon.
2. No. 2 and No. 3 rifle platoons. Same as No. 1.
(4) Equipment. There are in the company 150 rifles, 9 light machine guns, and 12 grenade dischargers.
o. Infantry rifle company ("A" type with heavy weapons platoon). (1) General. The company consists of a company commander, usually a captain, a company headquarters, 3 rifle platoons, a heavy weapons platoon, and an ammunition platoon. Total strength is 262.
(3) Strength analysis. (a) Company headquarters and 3 rifle platoons. 205 officers and men.
(b) Heavy weapons platoon. 46 officers and men.
(c) Ammunition platoon. Eleven men.
(4) Equipment. There are in the company 150 rifles, 9 light machine guns, 12 grenade dischargers, 2 heavy machine guns, two 20-mm antitank rifles.
p. Battalion machine-gun company (12-gun company). (1) General. This machine-gun company consists of a headquarters, a firing unit of 3 platoons (each having 4 heavy machine guns), and an ammunition platoon. The total strength is 174 officers and enlisted men.
(3) Strength analysis. (a) Company commander. Captain or First Lieutenant.
(b) Company headquarters (command section). 13 men.
(c) Firing unit (3 platoons, each 46).
1. No. 1 machine gun platoon.
2. No. 2 and No. 3 machine gun platoons. Same as No. 1.
(d) Ammunition platoon. 22 men. Noncommissioned officer in charge. 3 sections of 7.
(4) Equipment. The company has twelve 7.7 heavy machine guns.
q. Battalion machine-gun company (8-gun company). (1) General. The eight machine-gun company consists of a headquarters, a firing unit of 4 platoons (each having 2 heavy machine guns), and an ammunition platoon. The total strength is 144. It is this company which has been met most commonly in recent operations.
r. Battalion machine-gun company (4-gun company). (1) General. This company has only 4 machine guns; the other 8 of the normal battalion complement of 12 guns usually have been allocated to the rifle companies and are shown in the rifle companies' strengths. The company consists of a headquarters, 2 gun platoons, and a small ammunition platoon. The total strength is 73.
s. Battalion gun platoon. (1) General. The battalion gun platoon consists of a headquarters, a firing unit of 2 gun sections, and an ammunition section. Its total strength is 55 officers and enlisted men. It is equipped with two 70-mm battalion guns.
(3) Strength analysis. (a) Platoon commander. First or Second Lieutenant.
(b) Platoon headquarters (command section). Nine men.
(c) Firing unit. 30 men.
1. No. 1 gun section. Noncommissioned officer, two observers, 12 gunners.
2. No. 2 gun section. Same as No. 1.
(d) Ammunition section. 15 men.
(4) Equipment. The platoon has two 70-mm battalion guns.
t. Battalion gun company (without antitank rifles). (1) General. The battalion gun company consists of a headquarters, a firing unit of 2 gun platoons, and an ammunition platoon. Its total strength is 122.
(3) Strength analysis. (a) Company commander. First Lieutenant.
(b) Company headquarters (command section). Thirty-two men.
(c) Firing unit (two gun platoons, each 31)
(4) Equipment. The company has four 70-mm battalion guns.
u. Battalion gun company (with antitank rifle). (1) General. The battalion gun company consists of a headquarters, a firing unit of 2 gun platoons armed with 70-mm battalion howitzers, 4 platoons of 20-mm antitank rifles, and an ammunition platoon. Its total strength is about 230.
(3) Strength analysis. (a) Company commander. Captain or First Lieutenant.
(b) Company headquarters. 32 men.
(c) Firing unit. 158 men.
(d) Ammunition platoon. 39 men.
(4) Equipment. The company has four 70-mm battalion guns and eight 20-mm antitank rifles.
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 artillery regiment consists 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 armament is thirty-six 75-mm guns.
(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 a 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 composed of 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 headquarters 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:
c. Mountain artillery (pack). (1) General. Mountain artillery regiments 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 3000 to 3400 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.
(3) Strength analysis (estimate only).
(a) Regimental Headquarters. 150 men.
1. Administrative Section. 15 men.
2. Headquarters operational group. 135 men.
(b) Regimental train. 310 men.
(c) Three battalions (each 980). 2,940 men.
1. Battalion headquarters. 100 men.
2. Battalion train. 234 men.
3. Three gun companies (each 218).
(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 and 3 battalions of 75-mm field guns or 105-mm howitzers. When horsedrawn, the regiment numbers approximately 2,380 officers and enlisted men. This figure will decrease with the degree of motorization.
(3) Equipment. There is a total of twelve 75mm field guns and twenty-four 105-mm howitzers.
e. The medium artillery 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 divisions. (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 150-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.
(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 consists of a headquarters and train, 3 rifle and saber companies, and a machine gun company. The total strength is 950 officers and enlisted men.
(3) Equipment (estimate only).
(4) Strength analysis. (a) Regimental headquarters. Eighty-two men.
(b) Regimental train. Two hundred men.
(c) Three rifle and saber companies (each 170). Total 510.
(d) Three rifle and saber platoons (each 43). Total 129.
(e) One machine gun platoon. Twenty-four men.
(f) Machine gun company. One hundred fifty-eight men.
1. Two machine gun platoons (each 46).
2. One antitank gun platoon (37-mm). Twenty-seven men.
3. Ammunition platoon. Twenty-five men.
c. Cavalry regiment (modified organization). (1) General. The cavalry regiment consists of a headquarters, 2 rifle and saber companies, and a machine-gun company. Total strength is about 785 officers and men.
(3) Equipment (estimates only).
d. Reconnaissance regiment. (1) General. Reconnaissance units are divisional cavalry troops and may be used as an alternative to a cavalry regiment. The reconnaissance regiment consists of a headquarters, 1 cavalry company, 2 motorborne companies, 1 armored car (or tankette) company, and 1 motor-truck company. The total strength is about 730 officers and enlisted men.
(3) Equipment (estimates only).
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 consists of a headquarters, one light-tank company, two medium-tank companies, and a combat train. There are about 80 trucks included in the train.
c. Strength analysis.
14. ENGINEERS. a. The three-company regiment. (1) 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 requirement. If extensive engineer tasks, such as large scale bridging operations, have to be carried out, specialized engineer units are attached for the purpose.
(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 officers 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 each of light machine guns, grenade dischargers, mortars, and flame throwers.
(4) Companies are commanded by captains or first lieutenants and are composed of company headquarters, 4 platoons, and a material section. 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 tools and other 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 strength is about 240 men with 20 horses. Included as well, is a regimental headquarters and a material platoon, bringing the strength of the 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 consist 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, 3 to 5 field hospitals, and a water purification 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 of keeping 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.
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 accommodate 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.
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 diseases.
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 is assisted by two medical service noncommissioned officers, while medical service orderlies are attached to subunits on an average of one to a platoon.
16. TRANSPORT. a. General. The transport regiment has two 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.
b. Organization. (1) A standard division transport regiment is believed to be composed of a headquarters, one motor battalion, and one draft battalion. The draft battalion will be made up of three or four companies, with each company divided into three transport platoons, each of which in turn is divided into three sections. The motor battalion is believed to be made up of a 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 armored car transport company of 50 men. These units are in addition to the truck companies. The truck company has about 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:
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 a veterinary hospital staff with individual sections assigned during combat to the various divisional units.
18. ORDNANCE UNIT. Divisions also have ordnance 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 indicates that only the strongest divisions have an organic decontamination unit. Such a unit is 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. The 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 type 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 consist of 3 or 4 tank regiments plus a signal and engineer unit. (For the organization of a tank regiment, see sec. II, par. 3a (1).) Other evidence indicates that the Japanese may have formed armored divisions, of which the tank groups may be the nucleus.
b. Organization. Organization of such an armored division has been described as follows:
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 conditions and requirements.
b. Cavalry groups and cavalry brigades. (1) General. Japanese cavalry groups consist of two cavalry brigades, signal units, and trains.
(2) Organization of cavalry brigade.
(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 brigades. In addition to the infantry brigades assigned to the "special" division (see fig. 14) the Japanese have a number of independent infantry brigades. These brigades consist of four independent infantry battalions and a 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 1937-38 for garrison and antiguerrilla duties, are believed to be organized as follows:
The battalions consist of 3 or 4 companies, and 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 the present war 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 follows:
f. Amphibious brigades. (1) General. A new type of unit has recently 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:
The rifle companies were composed of three rifle platoons, of five sections each, a trench mortar platoon, and a heavy weapons platoon. The trench mortar company consisted of three platoons of four sections each, while the gun company had three mountain and two 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.
22. BORDER AND INDEPENDENT GARRISON UNITS. a. Border garrisons. Border garrisons are commanded either by major generals or colonels and vary in size. No. 1 Border Garrison, for example, is divided into four sectors, each under the command of a colonel. Each sector contains an infantry unit, an artillery unit, and an engineer unit. Most of the other border garrisons are not subdivided into sectors and contain only the three units, the infantry and artillery units being commanded by lieutenant colonels, and the engineer units by captains. It may be assumed that these infantry units are roughly equivalent to battalions. At present all the border garrisons are located in Manchuria.
b. Independent garrisons. Independent garrison units usually are commanded by major generals, although one or two are commanded by colonels. They contain three or four infantry battalions, but apparently no supporting arms or services. They are employed in rear areas.
23. FORTRESSES. a. General. The coastal defense fortresses in the Japanese Empire are to be found in Japan Proper, Korea. Formosa, the Bonin Islands, the Ryukyu Islands, the Pescadores, and Manchuria. These fortresses are commanded by officers ranging from lieutenant general to colonel, according to importance of the fortress. The fortress commander is responsible either to the commander of the army district or to the army commander in the area concerned. Fortification construction comes under the Fortifications Directorate which is responsible to the Chief of Staff.
b. Organization. The normal organization of fortresses is believed to be—
Armament includes coastal guns ranging from 4.7-inch to 12-inch caliber. It is probable that there are also 14- and 16-inch guns in some units.
c. The following are Japanese fortified zones:
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