Mitsubishi Ki-21 "Sally" - Army Air Academy

A chutai of Ki-21 Model 1 Ko, of the Army Air Academy (Koku Shikan Gakko) are practising formation flight.

The aircraft in the foreground is named "いよ" (IYo) after Iyo, a city in Ehime Prefecture, Shikoku Island.

Although they have a fuselage window next to the fuselage door, they don't yet have tail machine gun.