The Japanese semiauto rifle trials of the early 1930s had a total of four entrants – Kijiro Nambu and his company, Tokyo Gas & Electric, the Tokyo Army Arsenal, and Nippon Special Steel.
This rifle is one of the third iteration of the design from Nippon Special Steel. It is a design based originally on the Pedersen, but with substantial changes.
It is a toggle-locked and gas-operated action with a gas piston that moves forward upon firing. It feeds from a ten-round detachable box magazine, which is unfortunately missing on this example.
In total, 13 of these rifles were made for trials, with 4 of them actually being tested (and firing over 100,000 round between them without any extraction problems, apparently).
This rifle did have some accuracy problems, though, which would be fixed by its designer for the fourth and final trials, at which point it and the Tokyo Army Arsenal rifle were determined to be of equal quality – and then the whole program was dropped as the Marco Polo Bridge incident caused the Sino-Japanese War to quickly intensify.