New Nambu M57

The "New Nambu" M57 is a series of semi-automatic pistols designed by Shin-Chuō Industries, later merged with Minebea. "New Nambu" was named after Kijirō Nambu, a notable firearm designer and the founder of the predecessor of Shin-Chuō Industries.

Background
In the Empire of Japan, there were many semi-automatic pistols such as Nambu pistols designed by Kijirō Nambu, but after the Surrender of Japan, firearms development had all ceased. So law enforcement officials of Japan and military personnel of Japan Self-Defense Forces (JSDF) were equipped with American-originated firearms. With the policy of protecting industrial growth, the Ministry of International Trade and Industry (MITI) had been oriented to domestic production of service firearms.

In 1957, the development was started by Shin-Chuō Industries under the leadership of the MITI. The development of three handguns had been promoted at the same time in parallel. Semi-automatic pistols were completed as New Nambu M57, and the revolver became New Nambu M60.

Development was completed in 1958, but never entered service because of the problem of interoperability between the JSDF and the United States Armed Forces. Then, in 1970s, the JSDF restarted the trial for 9mm caliber pistols in conjunction with United States. Minebea, the successor of Shin-Chuō Industries, developed drastic modified version of the M57A for this trial. This version was completed as M57A1, but the JSDF selected SIG Sauer P220.

Design
M57A is a 9×19mm Parabellum caliber version of the American M1911A1, in essence. The M1911A1 was the standard service pistol of the JSDF, but its recoil was too strong for small-hand people such as average Japanese people, so small-caliber version was required.

M57B is a .32 ACP caliber semi-automatic pistol, based on the FN Model 1910, but firing mechanism is changed from striker to hammer.