Type 4 Ho-Ro

Inspired by the Grille series of self propelled artillery vehicles developed by Nazi Germany during World War II, wherein a 15 cm sIG 33 infantry support gun was mounted on a tracked chassis, engineers at the Army Technical Bureau resolved to do the same. Production was assigned to Mitsubishi Heavy Industries. The exact number produced in 1944 is uncertain, but was approximately 12 units.[2]

Type 4 15cm self-propelled gun Ho-Ro side view

The chassis selected was a modified Type 97 Chi-Ha chassis.[3] On to this platform, a Type 38 150 mm howitzer[3] which was based on a design by the German arms-manufacturer Krupp was mounted, but dated from 1905 and had been withdrawn from service as being obsolete in 1942.[4] The gun's elevation was restricted to 30 degrees by the construction of the chassis. The restricted elevation meant it was capable of firing a 35 kilogram shell 6,000 meters (6,600 yards). Given its breech loader, the maximum rate of fire was only 5 rounds per minute.[5] Other issue with the design was that the gun had a traverse movement of only 3 degrees. The gun crew was protected by a gun shield with armor thickness of 25 mm at the front,[6] but the shield only extended a very short distance on the sides, leaving the rest of the sides and back exposed. This made the design extremely vulnerable to close combat.

Top-angle view of Type 4 Ho-Ro

The Type 4 Ho-Ro was rushed into service and deployed in batteries of four, which saw combat as part of the 2nd Tank Division with the Japanese Fourteenth Area Army during the Philippines Campaign in the last year of World War II.[2][7] Remaining units were deployed to Okinawa in ones and twos for island defense during the Battle of Okinawa, but were severely outnumbered by American artillery.[4]

Type 4 Ho-Ro at the American Heritage Museum

A surviving example of a Type 4 Ho-Ro is located at the American Heritage Museum in Stow, Massachusetts. It is currently on loan from the National Museum of the Marine Corps and was captured on the island of Luzon in the Philippines.[8]

• Trewhitt, Philip (1999). Armoured Fighting Vehicles. Dempsey-Parr. ISBN 978-1840843286.
• Tomczyk, Andrzej (2007). Japanese Armor Vol. 5. AJ Press. ISBN 978-8372371799.
• Zaloga, Steven J. (2007). Japanese Tanks 1939–45. Osprey. ISBN 978-1-8460-3091-8.

• Taki's Imperial Japanese Army Page - Akira Takizawa
• Catalog of Enemy Ordnance