Type 4 Ho-Ro 15cm Self-Propelled Gun
Technical Information

Background
The Imperial Japanese Army (IJA) Type 4 Ho-Ro 15cm Self-Propelled Gun / 四式十五糎自走砲 ホロ was designed and built by Mitsubishi Heavy Industries. This self propelled gun was inspired by the German Grille (Cricket) self-propelled guns. In response, the Japanese Army Technical Bureau issued a request for a similar weapon. The self propelled gun was built on the chassis of a Type 97 Chi-Ha with a 150mm Type 38 (1905) Howitzer main gun but was limited to an elevation of only 30° and traverse of only 3°  due to the chassis. The self propelled gun had a crew of six.

The main gun was an older weapon withdrawn from service as obsolete and had a rate of fire of only 5 rounds per minute and with the elevation restriction could only fire a 35 kg shell at a maximum range of 6,600 yards / 6,000 meters The gun crew was protected by a 25mm armored shield from the front with limited protection to each side. Their rear and sides were unprotected. These limitations greatly restricted the effectiveness of the gun and made the crew extremely vulnerable. Despite these limitations, a small number were produced in 1944 and rushed into service.

Wartime History
During 1944, a small number of Type 4 Ho-Ro were transported to Luzon and assigned to the 2nd Tank Division and saw combat against the U.S. Army after they landed on Luzon in early 1945. A small number of Type 4 Ho-Ro reached Okinawa and participated in the Battle of Okinawa.

Production
Approximately 12 were built during 1944.

Technical Details
Crew  Six
Weight  16.3 Tons
Engine  Type 100 air-cooled V-12 diesel engine
Armor  12-25mm
Armament  150mm Type 38 (1905) Howitzer main gun