The Ho-Ro was built on a modified Type 97 Chi-Ha chassis. On to this platform, a Type 38 15cm howitzer was mounted. This gun was capable of firing a 79 lb shell 6,000 meters, but dated from 1905 and had been withdrawn from service as being obsolete in 1942. The gun crew was protected by an open gun shield with armour thickness of 25mm to the front, but was unprotected to the sides and rear, which made the vehicle extremely vulnerable to close combat. Other issues with the design were that the gun had a traverse movement of only 3 degrees, and had a slow rate of fire due to its breech loader. The Type 4 was deployed in batteries of four vehicles, which saw combat with the Japanese Fourteenth Area Army during the Philippines Campaign during the final months of World War II. Remaining units were deployed to Okinawa in ones and twos for island defence during the Battle of Okinawa, but were severely outnumbered by American artillery.