POTD: Not Last Ditch – Japanese Type 89 Knee Mortar
Sam.S 05.31.23
Welcome to today’s Photo of the Day! Here we have a good old leg breaker. This is a Japanese Type 89 “Knee Mortar”. The Type 89 of course gets its name from basically a guess at how they could function. they have an odd concave almost shoulder cup at the rear which allied soldiers guessed was to be used on a knee or thigh. In reality, the inertia from firing would really hurt someone so that was not the case. These also have the misconception of being a last-ditch weapon, most likely due to their simplicity but they were around in the late 1920s as a result of lessons learned in World War One.
“Originally developed in 1928, the Type 89 Mortar was a mainstay of Imperial Japanese forces through World War II. Lightweight, compact, and easily transportable by a single operator, the Type 89 was nicknamed the “Knee Mortar” due to an unfortunate misunderstanding of the design of the baseplate. Intended for use with a downed tree or similar rugged material, the smooth curvature made it a good fit for a human thigh or knee; any American attempting to use their leg as a firing platform was destined for a painful lesson in Newtonian physics (specifically regarding equal and opposite reactions) and a trip to a field hospital. Designed to be fired at a fixed angle, range control is accomplished via a threaded bolt assembly that extends through the breech, effectively reducing the barrel length as needed. A double-action style firing mechanism is integrated into the bolt. Matching numbers are present overall.”
Lot 1569: Japanese Type 89 “Knee” Mortar, Class III/NFA Destructive Device – World War II Japanese Type 89 “Knee” Mortar, Class III/NFA Destructive Device. (n.d.-n). Rock Island Auction Company. photograph. Retrieved May 30, 2023, from https://www.rockislandauction.com/detail/79/1569/japanese-type-89-knee-mortar-class-iiinfa-destructive-device.
