Type 89 Grenade Discharger

Japanese troops operate a Type 89 “Knee Mortar” in China

A unique light mortar used by the Imperial Japanese Military, the Type 89 Grenade Discharger would serve in the Battle of Manila, allowing individual Japanese infantry to have light mortar fire available. Commonly known as the “knee mortar”, due to the size as well as an early, erroneous US intelligence report suggesting the weapon was to be fired from the knee, the weapon was actually intended to be fired by planting it into the ground, and serious injury could result from firing it from the knee due to substantial recoil.

The weapon was a simple steel design, with a rifled launch tube attached to a smaller tube containing a combined spring driven striker. This was mounted to a curved plate that was intended to be braced into the ground or a tree trunk for firing, using either a modified hand grenade or a dedicated light mortar shell with a range of up to 120 meters (393 feet),

In the upcoming urban fighting in Manila, the Type 89 would be of less use in the confined streets as an indirect fire weapon, but would join machine guns to create kill zones on the streets and plazas of the city, with their light weight making them very mobile and almost impossible to destroy with counter battery fire like larger conventional mortars and artillery.