 The design was declared the winner of the competition, with a prototype (referred to as the 3MR4) being ordered from Blackburn.This first flew on 28 December 1929 at Blackburn's factory at Brough, Yorkshire, and was shipped to Japan in February 1930.Three development prototypes were built by Mitsubishi in Japan before the aircraft was adopted as the Navy Type 89-1 Model 1 Carrier Attack Plane or Mitsubishi B2M1.