Forerunner of the Type 14 Nambu that would be the standard Japanese sidearm of World War Two, the Grandpa Nambu was produced in relatively limited quantities well before the Papa Nambu was introduced, with only around 2,400 made by Tokyo Arsenal. The serial number of this Grandpa Nambu is recorded in "Hand Cannons of Imperial Japan" by Derby (page 44), where the survey reports Thai markings and a "short" style matching stock. A number of Grandpa Nambus are known to be so marked, though the exact circumstances behind it haven't been conclusively determined. Blade front and tangent rear sights, with the "stacked cannonball" Tokyo mark on the chamber, 3-symbol nomenclature on the right side and the Thai "sunburst" style mark visible on lower front gripstrap. The original pattern fixed lanyard staple and slotted backstrap are present and unaltered. Matching numbers are present overall, including the checkered grips and the nickel finished wood base magazine. The stock body is constructed from hardwood, with blued steel hardware, a matching serial number, and a telescoping neck for the mounting iron.

Fine as arsenal refurbished/subsequently professionally restored, with 90% of the blue finish, showing high edge wear, areas of light spotting and brown patina, and mild handling marks. The grips are also fine, with some chipping around the edges and minor dings. Mechanically excellent. The professionally restored stock is well polished with attractive grain and 95% plus blue finish on the renumbered to match hardware, though the neck and iron mechanisms need adjustment.