The Mitsubishi B1M was a Japanese torpedo bomber of the 1920s, also known as the Navy Type 13 Carrier-Borne Attack Aircraft.

[1] It went into Japanese Navy service as the Type 13-1 carrier-borne attack aircraft or B1M1 and was followed by the 2MT2 and 2MT3 variants (also designated B1M1).

The type entered service in 1924 and served into the 1930s, with thirty-two flying from the aircraft carriers Kaga and Hōshō during the Shanghai Incident in 1932.

[1] An aircraft from Kaga was lost during an aerial engagement between an American air force adviser and demonstration pilot to the Chinese government, Robert Short, who lost his life and was regarded as a hero defending the Chinese city against Japanese aircraft.

[3] From 1929, a number of surplus B1Ms were converted for civilian use, being fitted with an enclosed cabin for passengers or cargo.