was a Japanese smoothbore, muzzle loaded weapon used during the Second World War. It first entered service in 1921. The Type 10 has a range of 175 meters, greater than other grenade dischargers of that time. It had a range control device at the base of the barrel in the form of a graduated thimble by which a gas port at the base of the tube could be varied in size. For shorter ranges, part of the propellant gases escape to the side. Due to a translation error, the Type 10 was called the "knee mortar" by the Americans. The manual for the mortar instructed the troops to carry the mortar on the upper thigh, with the baseplate attached to the belt and the barrel running down the thigh. American troops on Guadalcanal became aware of the name "knee mortar" and thought the light design allowed it