The WWII Knee Mortar That Sold For A Surprising Amount On Pawn Stars

The pawnbrokers of "Pawn Stars" love guns — whether they be rifles, spearguns, or revolvers — but isn't there a little room in their hearts for grenade launchers? The Season 7 episode "Wouldn't It Be Ice?" answers this question with a resounding "Yes!" when seller Mike brings in a World War II-era Japanese knee mortar for Rick Harrison to inspect.

Mike's dad had served in WWII and brought some stuff back from his tour, including this deadly weapon. Designed in 1929, the Model 89 knee mortar was used to improve the accuracy of grenades — and with around 120,000 used during World War II, it's safe to say it got the job done to the satisfaction of the Imperial Japanese Army. What made the Model 89 knee mortar innovative was its portability: Unlike other mortars, the shape of this kind wasn't as clunky, and it didn't require any elaborate setup to use. Mike's Model 89 was deactivated after the war, with a metal bar welded across the mouth of its barrel and a hole sawed closer to its base. It isn't functional, but it could still be valuable.

Mike wants $2,000 for his knee mortar, and he tells the camera in his pre-sale interview, "I don't think that's unreasonable." We'll see!

Rick Harrison calls in weapons and military expert Craig Gottlieb to assess seller Mike's Model 89 knee mortar. That term — "knee mortar" — is not a translation from the original Japanese name for the weapon; rather, Craig tells Rick that American soldiers came up with the term from a misunderstanding of how the weapon was used. Other mortars are propped up on legs — sort of like a tripod — but the Model 89 only has a curved metal end that looks like it would fit above a soldier's knee, on the thigh. Looks can be deceiving, though, and Model 89s were actually thrust into the ground. That's much safer — for the weapon's operator, at least.

Rick's first question for Craig reflects the complicated rules that the pawnbrokers must follow when buying weapons: Is it legal to own? Craig replies with an unequivocal "yes," to Rick's delight, and the pawnbroker tells viewers in his pre-negotiation interview, "Now that I know it's legal to own, I would love to buy this. There's a lot of WWII collectors out there. This is one of those rare items that doesn't come up too often." But will Craig's appraisal of the Model 89 knee mortar be too high for Rick to pay?

With the legality of purchasing the Model 89 knee mortar cleared, the second most important question for Rick is this: How much is it worth? Craig says that the four-digit serial number on this knee mortar indicates that it was an earlier model, making it more valuable. However, he notes that although you can find Model 89s listed online for $5,000, they don't usually sell for that much. Craig says he would estimate the value of this Model 89 knee mortar to be $2,000, adding, "If I was selling it, I'd ask $1,995 — and probably get it."

After he leaves, Rick and Mike get into negotiations. Mike knows he's not getting $2,000 if that's the price Rick would want to sell it for — this would leave no room for the pawnbroker to profit — but when Rick offers $1,100 for it, Mike is bummed, as he had hoped for significantly more. So he counters with $1,500, and the two eventually settle at $1,250 for the Model 89 knee mortar — $50 higher than Rick had said was his ceiling. Clearly, he really wanted that weapon.

It'll likely be a bit slimmer profit than what Rick wanted to get out of the deal, but with an estimated net worth of $8 million, we think he'll be alright.