Given the codename "Grace" by the Allies, the B7A first flew as a prototype in May 1942, but teething problems with the experimental NK9C "Homare" engine and necessary modifications to the airframe meant that the type did not enter into production until two years later in May 1944. Nine prototype B7A1s were built and 80 production version B7A2s completed by Aichi before a severe earthquake in May 1945 destroyed the factory at Funakata where they were being assembled. A further 25 examples were produced at the 21st Naval Air Arsenal at Omura.