Aichi's design, with the company designation AB-12, was a single-engined biplaneflying boat of all-metal construction. Its two-bay wings folded rearwards to save space on board ship, while its crew of three were accommodated in an enclosed cabin. It was powered by a pusher water-cooled Aichi Type 91 engine, driving a four-blade wooden propeller.
The first prototype flew in December 1934, and when tested proved to have superior stability to the competing Kawanishi E10K, and so was ordered into production.
The AB-12 entered service in August 1936 with the Japanese Navy as the Type 96 Night Reconnaissance Seaplane, with the short designation E10A. Fifteen aircraft were built, remaining in service until 1941, being phased out before the Japanese Attack on Pearl Harbor. Despite this, it was assigned the Allied code nameHank.