The {{nihongo|Type 96 25 mm gun|九六式二十五粍高角機銃| Kyūroku-shiki nijyūgo-miri Kōkakukijū}} was an automatic cannon used by the Imperial Japanese Navy during World War II. A locally-built variant of the French Hotchkiss 25 mm anti-aircraft gun, it was designed as a dual-purpose weapon for use against armored vehicles and aircraft, but was primarily used as an anti-aircraft gun in fixed mounts with one to three guns. History and development In 1935 the Imperial Japanese Navy decided to replace the earlier 40 mm Vickers "pom-pom" guns with a 25 mm Hotchkiss design. A party of Japanese officers and engineers traveled to France to evaluate the design in 1935, and an order was placed for a number of guns and mounts for evaluation. Firing tests of these guns were conducted at Yokosuka Naval Arsenal in 1935. The first few weapons were built in France under the designation Type 94 and Type 95, with the mass production model produced at the Yokosuka Arsenal being designated Type 96. The Japanese made a number of minor changes to the original Hotchkiss design and production process, changing some components from forgings to castings to simplify production, and replacing the simple conical flash suppressor with a Rheinmetall-type design. A submarine-mountable version of the gun which made extensive use of stainless steel was also produced. The double-mount type was the first to enter service, with triple mounts following in 1941 and finally single mounts later in 1943. Design The Type 96 25mm gun is a simple air-cooled gas operated design. The barrel is a forging screwed into the breech mechanism. Additional support is provided to the breech end of the gun barrel by the finned cooling jacket. The barrel is changeable, requiring two men and special tools; the operation took a trained crew approximately five minutes. By adjusting the gas valve setting it was possible to vary the rate of fire between 200 and 260 rounds per minute, with 220 rounds per minute being the standard setting. The gun mounts were normally provided with one of three gun sights: A Le Prieur mechanical lead computing sight An open ring sight An etched glass optical ring sight Land mountings and all single mountings all used the single open-ring sight. The Type 95 sight was used on ship-based multiple mounts, in the case where the mount has a powered drive linked to a fire director it was used as a backup. The