Type 4 Ke-Nu

The Type 4 light tank Ke-Nu (四式軽戦車 ケヌ) was an innovation created to increase the number of light tanks available to front-line infantry divisions of the Imperial Japanese Army in World War II, through the re-use of obsolete components with little thought to quality or capabilities.

History and development
The original version of the Type 97 Chi-Ha tank had been armed with a low muzzle velocity 57 mm tank gun. Operation experience in Manchukuo, China in the early stages of the Second Sino-Japanese War and against the Soviet Union at Nomonhan during the brief Japanese-Soviet Border War in 1939 revealed that this gun was totally inadequate against any form of opposing armor, and a new higher velocity 47 mm tank gun was developed. This was then installed in the Type 97 Chi-Ha medium tank to produce the Type 97-kai Shinhoto version, which became the standard main battle tank of the Japanese army. This left a large number of surplus Chi-ha turrets, which were later retrofitted onto the chassis of the obsolete Type 95 Ha-Go light tank, which had been armed with a 37 mm tank gun. The result was designated the Type 4 Ke-Nu. In total, approximately 100 units were converted in 1944.

Design
Essentially a Type 95 Ha-Go with a Type 97 Chi-Ha gun turret, the Type 4 Ke-Nu had slightly better firepower, but at the expense of an additional ton in weight. This reduced the top speed of the tank to 40 km/h, but did nothing to alleviate the greatest weakness of the Type 95 Ha-Go – its lack of suitable armor protection for the hull. Maximum armor protection for the tank (25 mm) was provided by the Type 97 turret, and it was easily defeated by the 37 mm, 75 mm and 2-pounders mounted on Allied tanks.

Combat record
The conversion coming in 1944 was too late to make any impact on Japanese combat operations, and most of the Type 4 Ke-Nu were retained in the Japanese home islands against the projected American invasion. Some were assigned to units in Korea and Manchukuo, and saw brief combat against Soviet forces in the Soviet invasion of Manchuria. A surviving Type 4 Ke-Nu captured in Manchukuo is on display in Moscow at the Kubinka Tank Museum.