In this article, we will discuss the development of the Japanese Ho-Ri Tank Destroyer. With permission to post newly licensed documents dug up from the National Archive of Japan, we will review the history and production of Japan’s last tank destroyer of the war.

As the war progressed in the East, it became increasingly evident that Japan’s infantry-support based tank doctrine would not suffice against the growing threat from the United States. Aware of the American M6 Heavy tank, Japan decided to carefully review German tank doctrine. This new policy focused on the development and deployment of a common medium tank with stronger armament, which would in turn be supported by tank-destroyers with high-caliber weaponry.

Development of the Ho-Ri began in late 1943, using the chassis of the Type 5 Chi-Ri as the base for development. Japan’s 4th Technical Institute of Research understood that the Chi-Ri’s un-sloped frontal hull offered little protection against enemy anti-tank fire. A key focal point in the design of the Ho-Ri was the decision to angle the front armour plate to 70 degrees. The concept was presented to the Ministry of War in early 1944 in the form of a wooden mockup.

Following the presentation, the Ho-Ri was approved for construction, and in August of 1944, the first prototype had been constructed. Weighing in at approximately 35 tons, the tank had a speed of 40 kph using a Kawasaki Water-cooled V12 Engine, identical to that of the Chi-Ri medium tank, with a power output of 550 horsepower. Armour layout was also kept at similar specifications. Mounting an experimental high velocity 10.5cm tank gun, with an assistant loader mechanism, it achieved 150 millimeters of penetration at a range of 1,000 meters during trials. However, the Japanese Weapons Administration required more, and the gun was later revised.

The Ho-Ri prototype was approved for production for 1945, and was to be officially adopted into service under the designation Type 5. The production model of the Ho-Ri increased the thickness of the front hull plate to 120 millimeters. To compensate for the added weight of the increased armour an experimental Kawasaki V12 engine with an output of 1,100 horsepower was added.

Formal production of the Type 5 Ho-Ri began in January of 1945. By March, a total of 5 Ho-Ri tanks had been produced; further production of the vehicle was halted by American bombing raids. These vehicles were eventually destroyed or disposed of in deep lakes shortly before Japan’s surrender to U.S forces in order to prevent their capture and evaluation by U.S occupation forces.

Ref.C13120839500 The National Institute for Defense Studies, Ministry of Defense, Military Administration of Ordnance, 4th Technical Research Institute Details on Prototype Ho-Ri		Ref.C14011075200 The National Institute for Defense Studies, Ministry of Defense, Military Administration of Munitions Mobilization, Production Chart of January to April of 1945