Type 5 Chi-Ri

The Type 5 medium tank Chi-Ri (五式中戦車 チリ) was the penultimate medium tank developed by the Imperial Japanese Army in World War II. Intended to be a heavier, more powerful version of Japan's sophisticated Type 4 Chi-To medium tank, in performance it was designed to surpass the US M4 Sherman medium tanks being fielded by the Allied forces. The single prototype was still being built when the war ended.

History and development
A single unarmed prototype of the Type 5 Chi-Ri was completed by May 1945. The project was abruptly abandoned to free up manpower and critical resources to concentrate on the development and production of the more practical Type 4 Chi-To medium tank. As with many innovative weapons projects launched by Japan in the final days of World War II, production could not advance beyond the prototype stage due to material shortages, and the loss of Japan's industrial infrastructure to the Allied bombing of Japan.

Design
The Type 5 Chi-Ri featured a lengthened version of the Type 4 Chi-To chassis, with eight road wheels per side instead of the Chi-To's seven. It had the usual Japanese track arrangement with forward mounted drive sprockets and rear mounted idlers. The Type 5 Chi-Ri had sloped welded armor, with a maximum thickness of 75 mm at the front; 25–50 mm on the side; 50 mm on the rear.

The Type 5 Chi-Ri was initially to be powered by a Mitsubishi Diesel engine, but the advancements needed to provide the necessary horsepower fell behind schedule, and a 800 hp V-12 gasoline-fueled aircraft engine designed by BMW in Germany and licensed to Kawasaki Heavy Industries in Japan was selected instead. The "Kawasaki Type 98 800 HP engine Ha-9-IIb" was detuned for the tank to 550 hp.

Originally, the prototype tank was to be fitted with the same Type 5 75 mm Tank Gun (based on the Type 4 75 mm AA Gun) used on the Type 4 Chi-To. However, eventually an 88 mm gun (based on the Type 99 88 mm AA Gun) was planned for the turret; a secondary weapon of a front hull-mounted Type 1 37 mm tank gun was fitted in the position normally taken by a machine gun. There was a ball mount for a Type 97 light machine gun on the left side of the turret for use in close combat situations. According to another source, the design called for two Type 97 light machine guns.

Service
As with the Type 4 Chi-To medium tanks, the Type 5 Chi-Ri tanks were earmarked for the final defenses of the Japanese home islands against the expected Allied invasions. Army planners envisioned large armored divisions equipped with the Type 5 medium tanks driving the invaders back into the sea, but the war came to an end before even the first prototype could be completed.

The single prototype Type 5 was seized by American forces during the occupation of Japan, but its subsequent fate is unknown. One theory is that it sank in the ocean when a freighter taking it to the Aberdeen Proving Grounds capsized in a typhoon; another theory is that it was scrapped for its metal armor during the Korean War.

Variants

 * Ho-Ri tank destroyer
 * The Ho-Ri was a more powerful tank destroyer (gun tank) version of the Type 5 Chi-Ri, using a 105 mm cannon in place of the 75 mm design. This design was possibly inspired by the German Ferdinand/Elefant heavy tank destroyer. No prototype was built.