This is a scarce example of a WWII Japanese Type 97 Naval Aircraft medium machine gun. It comes with a detailed description on the history of the weapon from Springfield Armory Museum based on the fact that they have one of these weapons in their collection. These were used only on A6M "Zero-Sen" Japanese Naval aircraft, mounted in pairs on top of the cowling to fire through the propeller or sometimes mounted in the leading edge of the fighters wing. These are a very close copy of the British Vickers-Maxim medium machine gun, as the Vickers company signed a license agreement with the Japanese Government in 1936, (which stayed in affect until 1941), allowing them to use that design. This specific type of machine gun was only manufactured by two companies: the Nippon Seikosho company (Japan Steel Works) at Torokamenachi Iango-ku, Yokohama, and the Yokosuka Naval Arsenal in Yokosuka. These were a very unique weapon in that they had a baked on all "black painted" type finish in lieu of the traditional blue finish designed to resist corrosive salt spray while still providing a very durable finish. They were also designed to feed from either the right or left hand side and were not interchangeable like the U.S. made machine guns. This was so that they could be mounted on top of the airplane's cowling, so that each one could be cocked from either the right or left side. They also had a very interesting top cover in that it was hinged on the side and not on the front of the front like the U.S. made machine guns. The cocking and top cover mechanism were not interchangeable; however, the feed trays could be used on either gun. This was designed to match which side the cocking mechanism was on, i.e. a right hand cocking lever had a left hand side hinged top cover and vice a versa. This example also has what looks like a mechanical interrupter mounted on the top portion of the machine gun and which is stamped "1531/1B". This maybe the symbol for the Yokosuka Naval Arsenal at Yokosuka, (as the Springfield Armory weapon is stamped "B874" which was the symbol for the other company). If correct, we assume it was designed to be attached to a cam shaft somewhere to ensure that the gun stopped firing when the propeller was inline with the barrels. The rear area of the top cover is marked: "97-77 3-2/6579" over three Japanese proofs. The top of the feed tray is stamped with serial number "6975". The bolt mechanism and front area of the top cover serial numbered "6579". There were obviously some numbering errors at the factory. The only other markings on the weapon is a small Japanese Naval Anchor proof on top of the barrel trunion. Currently, it is mounted on a professionally made wooden display board.

Fine condition with 45% of the original baked on back finish still remaining overall with the balance of the metal a dark brown patina finish. A very rare and certainly very interesting naval aircraft machine gun. NOTE: This weapon is a National Firearms Act (NFA), Class 3, which is registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives, (BATFE) under the provisions of 18 U.S.C. Chapter 44 and 27 CFR part 478.