[Lone Sentry: WWII Tactical and Technical Trends]
[Lone Sentry: Photos, Articles, and Research on the European Theater in World War II]
Photos, Articles, & Research on the European Theater in World War II
Home Page | Site Map | What's New | Intel Articles by Subject

"Japanese Light Tank" from Tactical and Technical Trends

A report on Japanese light tanks in WWII, from Tactical and Technical Trends, No. 31, August 12, 1943.

[DISCLAIMER: The following text is taken from the U.S. War Department publication Tactical and Technical Trends. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]


a. General

Three basic designs of Japanese tanks have been encountered in Southern Asia and the Southwest Pacific. The "tankette" is a lightly-armored machine-gun carrier of from 3 to 4.5 tons, which has had many models. The light tank, of from 7 to 9 tons, which mounts one 37-mm gun and two machine guns, has also appeared in several variations. The medium "cruiser" tank, mounting a 57-mm gun and either two or three machine guns, weighs from 14 to 16 tons. This latter model may also be encountered fitted with a 47-mm or other caliber gun in place of the 57-mm weapon. A larger tank, of from 25 to 28 tons, is known to exist but has not yet been met with in any theater of operation.

A report from Australia on a Japanese light tank, (see sketch) a variation of Model 2595, captured at Milne Bay draws attention to the following features not included in the "Handbook on Japanese Military Forces" published last September as TM 30-480.

(1) Exceedingly cramped fighting compartment;

(2) High quality of workmanship, material, and excellence of design generally;

(3) Solidly constructed Carden-Loyd type suspension with the weight of the vehicle supported by horizontal compression springs, protected by curved 4-mm (.16 in) armor plate;

(4) Adequate provision of exits for all personnel;

(5) Exceedingly fine workmanship on all transmission components, with extravagant use of self-aligning ball bearings;

(6) All gears are profile-ground, and mating surfaces of gear boxes and housings are hand-scraped for accuracy. Transmission gears are not case-hardened, but are heat-treated;

(7) Ball races are either of German manufacture or else have no name or type number imprinted on them;

(8) Combined rivetted and welded construction of hull, the whole being built around a channel- and angle-iron frame;

(9) Design generally very light, with extensive use of aluminum and light alloys;

(10) Lightly armored, the maximum thickness of armor being .47 inch even for the vertical plate at the rear;

(11) Insulation of the engine compartment against heat from outside sources and to prevent the heat from the engine penetrating to the fighting compartment;

(12) Woven asbestos paddings, separated from the inside surfaces of the tank by an air space, to prevent direct radiation from the hull to the crew in hot climates, and also to guard against injury to the crew when travelling over rough ground;

(13) Numerous vision slits at vital points, but unprotected by glass visor-blocks except directly in front of driver,

(14) Sturdy air-cooled Diesel engine;

(15) High power-weight ratio (approximately 25 HP per ton).

b. Comparison with the German PzKw 2

The Jap light tank and the PzKw 2 are of about the same vintage.

They compare as follows:

    Jap Lt Tk     PzKw 2  
   Weight (in action)8-9 tons9-10 tons
   Length14 ft 4 1/2 in15 ft 5 in
   Width6ft 9in7ft 3in
   Height7 ft 0.5 in6 ft 6 in
   Clearance15.5 in13 in
   Front.47 in.79 in
   Sides.47 in to .39 in.71 in
   Rear.47 in.71 in
   Turret.47 in.79 in
   Top.35 to .24 in.59 in
Armament1 37 mm1 20 mm
 1 MG (in turret, right rear)1 MG (coaxial, in turret)
 1 MG (in hull, forward) 
Engine 6 cyl in line OHV Diesel, 240 HP at 2,000 rpm, air cooled, 5.12 in bore, 7.09 in stroke compr. ratio 15.05:1 Maybach, 6 cyl OHV gasoline, 140* HP, water cooled
Speed28 mph25 to 36 mph
Fuel capacity29 gal44 gal

*Rated hp; the engine would probably develop considerably more actual power than the Japanese at about 1,800 rpm.

The German tank would appear to be the better of the two.

[WWII Japanese Light Tank]

c. Additional Details of the Japanese Tank

(1) Armor

The .47 inch armor is face-hardened; the .35 inch, is non-machineable homogeneous plate, only slightly softer than the .24 inch, which is homogeneous hardened. The recoil mechanism of the 37-mm gun is protected by a manganese steel casting, and the machine guns by hardened pressed steel sheaths.

(2) Ammunition Carried

For the 37-mm gun, 130 rounds are carried and for the machine guns, 2,340.

(3) Engine and Drive

On a fighting weight of 9 tons, power-weight ratio is 26.7 HP per ton. Fuel is carried in a main tank of 23 gallons with six in the reserve. The clutch is of the multi-disk type bolted to the fly-wheel, operating through a manual-control gear box with four speeds forward, one reverse. The steering is of the clutch-brake principle, with multi-disk clutches working external contracting type brake drums and operated by steering levers. The suspension is front drive sprocket, rear idler, with 4 bogie wheels in pairs on bell cranks, sprung by compression springs.

(4) Tracks

The tracks are full floating, of manganese steel, 10 inches wide. Ground contact is 7 feet 8 inches, giving a pressure of 9.9 pounds per sq inch.

(5) Intercommunication

The communication system is by radio.

Comment: The light armor and unprotected vision slits would seem to make this tank rather vulnerable, even to rifle and machine-gun fire. Japanese tanks are not manufactured on the assembly-line system; consequently, several variations of the original design will be encountered. Improvised mechanized units have been used by the Japanese in China repeatedly with considerable success. Such units, while probably without elaborated tables of organization and equipment, are organized on the basis of expediency and availability of materiel with the usual reconnaissance, ground-holding, shock, and supply components which characterize the mechanized brigades and divisions of foreign armies.


[Back] Back to Articles by Subject | Intel Bulletin by Issue | T&TT by Issue | Home Page


Web LoneSentry.com