Type 2 Ho-I

The Type 2 gun tank Ho-I (二式砲戦車 ホイ, Ni-shiki hōsensha Ho-I) was a derivative of the Type 97 Chi-Ha medium tanks of the Imperial Japanese Army in World War II. Similar in concept to the early variants of the German Panzer IV, it was designed as a self-propelled howitzer to provide the close-in fire support for standard Japanese medium tanks with additional firepower against enemy anti-tank fortifications.^[2]

Type 2 Ho-I
Type 2 Ho-I gun tank
Type	Infantry support tank Assault gun
Place of origin	Empire of Japan
Service history
Used by	Imperial Japanese Army
Production history
Produced	1944
No. built	31[1]
Specifications
Mass	16.1 tons
Length	5.73 m (18 ft 10 in)
Width	2.33 m (7 ft 8 in)
Height	2.58 m (8 ft 6 in)
Crew	5
Armor	12–50 mm
Main armament	75 mm Type 99 gun
Secondary armament	1 x 7.7 mm Type 97 machine gun
Engine	Mitsubishi Type 100 air cooled V-12 diesel 240 hp (179 kW)
Power/weight	14.9 hp/tonne
Suspension	bellcrank
Operational range	100 km
Maximum speed	44 km/h (27 mph)

History and development

Experimental Type 1 gun tank Ho-I, 1941

Design work on the Type 2 Ho-I began in 1937, after experience in Manchukuo taught Japanese war planners that an armored vehicle with a larger weapon would be useful against fortified enemy positions such as pillboxes, against which the standard low-velocity 57mm and high-velocity 47mm tank guns were ineffective. Since this vehicle was to be able to keep up with the rest of an armored formation, the Japanese began work on mounting a Type 41 75 mm mountain gun onto the chassis of the Type 97 Chi-Ha medium tank. The adapted mountain gun, known as the Type 99 75 mm tank gun, was completed in 1940. The gun could fire an assortment of ammunition, including a 6.6 kg (14.5 lb) armor-piercing shell and had a muzzle velocity of 445mps. By 1942 the Type 99 75 mm gun was fitted into a modified Type 97 Shinhōtō Chi-Ha turret, which resulted in the designated Type 2 Ho-I gun tank.^[1][2] The Type 2 Ho-I gun tank was intended to be part of a fire support company in each of the tank regiments.^[1]

Design

Experimental Type 1 gun tank Ho-I, side view

Type 2 gun tank Ho-I, side view

The 1941 prototype model, known as the Experimental Type 1 Ho-I, used the Type 97 Chi-Ha chassis. The production model utilized the chassis of the Type 1 Chi-He medium tank, which was itself a modified Type 97 Chi-Ha hull.^[3][4]

The main armament of the Type 2 Ho-I was a Type 99 75 mm tank gun, and secondary armament was a single 7.7 mm Type 97 light machine gun in the hull.^[4] The short barreled 75 mm Type 99 gun was mounted in a gun turret of the type used for the Type 97 Shinhōtō Chi-Ha tank with modifications to accommodate the gun used and the addition of a large rear hatch.^[1][5]

Service history

As with other tanks and self-propelled guns, production was hampered by material shortages, and by the bombing of Japan in World War II. All 31 Type 2 Ho-I tanks produced were conversions from existing Type 1 Chi-He medium tanks.^[6] There is no record of a Type 2 Ho-I being used in combat prior to the end of the war.^[2][4]