Nambu Mark A/B Sword Pistol
- Nambu Mark A Sword Pistol - Was the first prototype. It had a distinctive trigger guard and a long guntou blade. (Built on the basis of Type B Small.)
- Nambu Mark B Sword Pistol - Was the second prototype, construction was simplified. The blade of the sword was also shortened and it had a shorter barrel. (Built on the basis of Type B Small.)
In the 1920s, four Small-Model pistols were heavily modified in an experiment to create a pistol sword. These "Baby Nambus" featured a significantly longer grip (which also gives them notably higher-capacity magazines, though the actual capacity is unknown) and a guntou blade built into the right-side grip panel. At least one of the pistols had its trigger guard replaced with a large full-hand sabre-like guard, while another had a shorter barrel and no sights. Although presumably highly unwieldy, the blade does not mechanically affect the pistol and thus it should otherwise function like a regular Nambu. Similar experiments with the Mark B Pistol (Nambu Type 14) were conducted a few years later as well.
At least one of these pistols evidently survived, as one is known to exist in a US military museum collection, though the pistol is missing virtually all of its components, leaving only the frame, barrel, grips, and blade. A photo of this pistol (seen below) has been fairly widely circulated on the internet, and due to it being a photo of the non-functional "hulk" of a pistol, this has created potentially even more confusion in Western circles about whether this was actually a functional pistol (which it was).