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
(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
(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
(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
(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 tons||9-10 tons|
| Length||14 ft 4 1/2 in||15 ft 5 in|
| Width||6ft 9in||7ft 3in|
| Height||7 ft 0.5 in||6 ft 6 in|
| Clearance||15.5 in||13 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|
|Armament||1 37 mm||1 20 mm|
| ||1 MG (in turret, right rear)||1 MG (coaxial, in turret)|
| ||1 MG (in hull, forward)|| |
||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|
|Speed||28 mph||25 to 36 mph|
|Fuel capacity||29 gal||44 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.
c. Additional Details of the Japanese Tank
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
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.
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.