This is a very interesting Japanese 1902 Papa Nambu pistol chambered in 8mm Nambu.  Although this pistol shows poor condition and missing parts, it does retain the original capture tag from the US service member who brought it home. It is unfortunate that it is in the condition that it is in, but this is how it came from the estate.  This would be a great addition to your collection if you collect Pacific War bringbacks with provenance.