The Type 89 Grenade Discharger (八九式重擲弾筒 Hachikyū-shiki jū-tekidantō?), inaccurately and colloquially known as a knee mortar by Allied forces, is a Japanese grenade launcher or light mortar that was widely used in the Pacific Ocean theatre of World War II.
The type 89 Knee Mortar was one of the most popular Japanese grenade dischargers before and during the Second World War. It was produced from 1926 to 1945. Because the Type 89 mortar was so small it was ideal for the Pacific Islands campaign ( 1941-1945). With plenty of ammunition available the mortar saw intensive action when the American Marines attacked islands, occupied by the Japanese.
Usage by the Japanese
The Type 89 Knee mortar was seen being fired by a Japanese soldier in the Battle of Peleliu airfield in Part 6 of the Series. In the same part of the series it is shown laying by a dead Japanese foot soldier during the Airfield battle.