UPDATE: Regarding the serial number plates, my guess is that they are not original to the jeep. 

Also, Derek Redmond provided his thoughts on this jeep: “The 3B you sent is unusual indeed. You didn’t mention whether you noticed the serial number plate is from a 1953 stripped chassis 3B.  But there’s nothing that really ties that to the Jeep itself.  You’re correct about it being a Mitsu, although an earlier model than the one you found on my site.  The drawing athttps://cj3b.info/World/JapanJ4.html is pretty much identical – it would be an early 1953 CJ3B-J4.

I guess it could be just a Mitsu body dropped on the stripped chassis. I don’t know enough about Mitsu mechanical parts to tell if there are any clues in the photos.

The little bracket welded to the grille is definitely for a Japanese unit badge. The one on the driver’s side of the dash could also be for some military thing like a rifle holder, although I don’t recall seeing one before.

The fuel filler, hood cutout, glovebox, bumperettes, blackout marker lights, lack of tailgate and the windshield all say Mitsu military. The windshields almost always had a vent in the center, but some of the very earliest did not, probably when the stampings were still coming from the US. 

I have seen some Mitsu under hood photos that look like they possibly show those brackets on the fender, but it’s hard to tell.  Same with the drawing.”

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This unusual “CJ-3B” has a number of odd elements. Given the passenger indents, I thought this might have a replacement body. However, the lack of a tailgate, the unusual passenger fender, the grille with a metal piece welded between the tines, and the split windshield suggested to me that this might be something else.

https://sacramento.craigslist.org/cto/d/galt-1953-willys-cj3b-jeep/7508566765.html

“1953 Willys CJ3B Jeep
Needs restored!
1953 Willys CJ3B Jeep
Needs restored!
Comes with rebuilt 4 cylinder Hurricane flathead motor; not installed.
Title lost. Been stored for 39 years. Owned for 54 years!
Miscellaneous parts”