Type 89 Light Mortar

Japanese soldiers using a Type 89 Light Mortar

The Type 89 Light Mortar, Type 89 Grenade Discharger, or "Knee Mortar" was a small mortar used by Japan during WWII. It fired 50mm Type 89 Shells and could even be fitted to fire the Type 91 Grenade. The rate of fire for the mortar was about 25 rounds per minute.

The Type 91 Grenade was primarily used in the jungle where there was a significant chance that any mortar round would hit something on its way to the target. This is where the 7-8 second delay came into action. The firing pin was also adjustable so the range could be set; the higher the firing pin was set, the lesser the distance the shell would go.

There were no sights for aiming, only a line on the barrel and the maximum range was about 670 meters. Due to bad translation American's thoght the weapons was called the "Knee Mortar". Many soldiers lost and hurt there legs because of this but in reality it was meant to be fired resting the ground or another solid object. The spade-type support at the back of the of the Type 89 was meant to be angled at about 45 degrees and sometimes it could be positioned pointing straight against a tree.

Firing from the knee would cause several injuries including broken bones. The empty weight of the mortar was 4.7 kg and the length was 61 cm. The Type 89 was also capable of being disassembled into three main components and being reassembled at the desired location. There were no variants of the Type 89 and it was made as better version of the earlier Type 10 Mortar.

History

The Type 89 Light Mortar was developed in 1929 and it was uses in many different places in the Pacific theater. Some of these include China, Burma, and some other pacific islands. It had a certain psychological effect on allied troops and some learned to recognize the Type 89 Mortar by its "pop" sound when firing. The effectiveness was mixed, but overall it was fairly good.