A rearmed Ha-Go

The Type 4 Ke-Nu was created to provide improved fire support to combat engaged IJA divisions all around the Pacific theater. At the same time, the upgrade of the original Type 97 Chi-Ha medium tank was taking place. It swapped, in 1942-43, its short low velocity Type 97 57 mm (2.24 in) main gun with a newer high velocity, long barrel, Type 1 47 mm (1.85 in) anti-tank gun in a modified turret to increase its firepower, range and increase internal space. This left the many original Chi-Ha turrets with no purpose to fulfill. Many were sent to reinforce fixed defenses on various islands, but others were available for any kind of chassis-turret marriage.

Specifications

In 1942, the General Staff ordered a study of converting obsolescent Ha-Go chassis with these spare Chi-Ha turrets. The Ha-Go was, at the time, armed with a Type 94 37 mm (1.46 in) gun with limited anti-tank capabilities. At the same time, more efficient HE and AP rounds had been issued for the Type 97 57 mm (2.24 in). The resulting conversions made the new model one ton heavier and, subsequently, reduced its original top speed from 28 mph (43 km/h) to just 25 mph (35 km/h). Approximately 100 (factory conversion records are complicated to track) of this hybrid were delivered in 1944. It appeared that many (if not most) were converted as radio tanks, with the characteristic horse-shoe antenna.

The Ke-Nu in action

Battle records of the type include Manchuria and Korea in 1945, but they saw little or no combat. Others were stationed in Okinawa and Kyushu, in prevision of the expected Allied invasion. A single one was captured by the Soviets in August 1945, during the invasion of Manchuria, and now is displayed at the Kubinka museum.

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Type 4 Ke-Nu specifications
Dimensions	4.38 x 2.06 x 2.18 m (14.37 x 6.75 x 7.15 ft)
Total weight, battle ready	8.4 tons
Crew	3 (driver, commander/gunner, machine-gunner)
Propulsion	Mitsubishi A6120VD air-cooled diesel, 120 hp (90 kW)@1800 rpm
Speed	35 km/h (25 mph)
Armor	6 to 16 mm
Range (road/off road)	200 km (125 mi)
Total production	100