Gilbert and Marshall Islands campaign
Two specimens of the Type 3 81 mm mortar were captured in the Marshall Islands during the Gilbert and Marshall Islands campaign which occurred between late 1943 and early 1944. They are marked "Type 3 81 mm Trench mortar made in 1943, Yokosuka Navy Arsenal". Despite the Type designation, the mortar was believed to be a forerunner of the Type 97 81 mm infantry mortar, the base plate of which can be used with the Type 3.