In the late 1930s, Seversky aircraft exported twenty two-seat 2PA-B3 to Japan for operational service by the Imperial Japanese Navy Air Service as the A8V1 Type S Two Seat Fighter. The aircraft were imported as a result of Japanese anxiety over escalating losses for their unescorted strategic bombing raids with Type 96 G3M bombers deep into China from bases in Formosa (Taiwan) which had begun in 1937. The purchase contract for the Seversky 2PA-B3, construction numbers 122 through 141 had been negotiated secretly but was to cause controversy in the US and subsequent difficulties in Seversky's relationship with the US government and military. Sources differ on exactly when the aircraft were delivered, but it must have been at least prior to October 1938 (see below).