After building 57 Nieuport 81 trainers for the Imperial Japanese Army as the Mitsubishi Ko-1, followed by 145 Hanriot HD-14s under the designation Mitsubishi KM, Mitsubishi submitted the experimental 2MB2 Washi two-seat light bomber biplane designed by Alexander Baumann in 1925. This was rejected for production, the Imperial Army preferring Herbert Smith's more conventional 2MB1, a large two-seat biplane with wide-track divided landing gear. This entered service in 1927 as the Army Type 87 Light Bomber, 48 being built, and each was powered by a 336kW Hispano-Suiza engine which gave a maximum speed of 185km/h; the 2MB1 had a maximum take-off weight of 3300kg and wing span of 14.80m. Armament comprised one fixed forward-firing 7.7mm machine-gun, twin guns of the same calibre on a ring mounting for the observer, and provision for a fourth gun firing through a ventral trap; maximum bomb load was 500kg.