[3] It was necessary to import all of its military aircraft and engines as there was no aviation manufacturing industry in Japan at that time.

To remedy this, Japan began importing state-of-the-art aircraft from around the world, and after close examination and study they incorporated the best features of each into their own design, thereby creating a uniquely superior Japanese designed and built product.

The Southampton was a twin-engine biplane flying boat, with the 500 hp (373 kW) Napier Lion VA W-block tractor engines mounted between the wings.

After performance testing at Yokosuka, the Southampton was ferried to the Hiro Naval Arsenal for further study.

Those features included an all-metal hull and simplified construction, both of which the Japanese Navy hoped to incorporate into the replacement for the outdated Type 15 Flying-boat.