| Type 10 grenade discharger | |
| Origin: | Empire of Japan |
| Type: | Light mortar |
| Is Ranged: | yes |
| Is Artillery: | yes |
| Service: | 1921–1945 |
| Used By: | Imperial Japanese Army |
| Wars: | Second Sino-Japanese War, World War II, Indonesian National Revolution, Malayan Emergency, Korean War |
| Design Date: | 1918-1920 |
| Production Date: | 1921-1937[1] |
| Weight: | 2.6kg (05.7lb) |
| Length: | 525 mm (20.7 in) |
| Part Length: | 240 mm (9.5 in) |
| Cartridge Weight: | 0.53kg (01.17lb)[2] |
| Caliber: | 50 mm (1.97 in) |
| Range: | (Type 91 grenade): 65 m (71 yd) |
| Max Range: | (Type 91 grenade): 175 m (191 yd) |
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 175m (574feet), 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.[3]
The manual for the mortar instructed the troops to carry the mortar on the upper thigh, with the base plate attached to the belt and the barrel running down the thigh. It was not strapped or secured directly to the thigh. It was also carried strapped to the backpack. American troops on Guadalcanal became aware of the name "knee mortar" and thought the light design allowed it to be fired with the base plate resting on the thigh. If the Type 10 were fired in this manner, it would result in serious injury due to recoil. However, once a few troops injured themselves, the mistranslation was discovered and further experimentation discouraged.
World War II era US intelligence thought that the weapon was primarily used to discharge signal flares, the larger and heavier Type 89 grenade discharger being used to fire explosive rounds instead. This assessment was largely correct, although the Type 10 grenade discharger could fire and was issued with the Type 10 high-explosive shell. [4]