Ah, knee mortars.
They weren't mortars and they had nothing to do with knees. They were the Imperial Japanese Army's standard grenade launcher. And they were one of the great unsung weapons systems of World War Two.
Light, cheap, simple, easy to carry and maintain, and utterly ubiquitous. One of the few weapons systems where the Japanese managed to outproduce everyone else. The Brits and Americans averaged two or three grenade launchers per infantry company. (The Marines were an interesting exception. The USMC was very sensible about mortars.) The Japanese had one per /squad/. And while their throw weight was light, these little monsters could drop a grenade on your head from 600+ yards away with terrifying accuracy.
They were simple, but they weren't primitive. Their clunky, ugly appearance belied a great deal of careful thought and development. The engagement mechanism for the rifling was elegant, but also easy to disassemble and clean, and made of a copper alloy that had exactly the right mix of flexibility and strength. The whole thing could be broken down into four lightweight pieces, just a few pounds each, which could be carried without difficulty by various squad members then reassembled in a few moments.
Sighted with two lug nuts -- a monkey could do it. But in practiced hands (and because they were ubiquitous and cheap, there were a lot of practiced hands), amazingly accurate. Fully functional under conditions from rain forest downpour to Aleutian blizzards. Easy to use, almost impossible to break.
Read any US memoir of the Pacific War, and you'll realize just how much American soldiers came to hate and fear these things. Knee mortars probably killed far more Americans than Zeroes or Long Lances ever did, and at a tiny fraction of the cost.
All the other combatants had grenade launchers too, of course. But they tended to be bigger -- the standard US 60mm launcher weighed 43 pounds as opposed to 12 for the knee mortar -- and much less common.
(True, the US grenade launcher had a throw weight about 50% greater and nearly three times the range. But not many WWII infantry actions took place at a range of 2000 yards. To simplify a complex reality, the US weapon was overpowered.)
So, a question: WI we give the knee mortar to some other power's infantry? -- When I say "give the knee mortar", I mean not just the weapon but the whole package: they're light, cheap and reliable, every squad has one, and they're a strongly preferred method of making the enemy miserable.
This seems like something the Russians or Americans would have figured out, doesn't it? Oddly, not.
The Germans... um. Tempting as it is to give the Wehrmacht something this nasty, "light, cheap, reliable and mass-produced" don't seem a perfect fit.
Thoughts?
Doug M.