Inspired by German self-propelled guns the Type 4 Ho-Ro assault gun was based on a reinforced Type 97 Chi-Ha tank chassis. The Type 4 Ho-Ro mounted the Type 38 150mm howitzer. Surrounding the front of the howitzer was 25mm of armour plating – the open rear leaving the crew susceptible to close combat and shrapnel.
 
The 150mm gun predominantly fired Type 88 APHE (armour-piercing high explosive) rounds although it could also fire HEAT (high explosive anti-tank) shells. Ammunition was stored in a container on the rear engine deck.
 
Rushed into service towards the end of World War II, the Ho-Ro was deployed in batteries of four vehicles. It saw action during the Philippines Campaign and during the American assault on Okinawa where it was heavily outnumbered by US artillery assets.
 
Principal service: 1945.
Numbers manufactured: 25.
The Japanese did not produce any tanks of their own until 1929 and the first examples were versions of contemporary British and French models from Vickers, Renault and Carden-Lloyd. Experience in Manchuria caused the Japanese to use Russian armour as a model.
 
However, heavy armour played a minor part in Japan’s military strategy, and by the time her armies were obliged to face modern enemy tanks it was already too late. Such tanks as were available were lightly armoured and poorly armed compared to those used by the Allies.
 
Outgunned as they were by enemy armour they could still be effective against troop formations and many were adapted to carry other weaponry such as the 150mm howitzer married with the Chi-HA to produce the Ho-Ro Assault gun