Mitsubishi Ki-21 "Sally"

Moky sent over this very interesting photo from his collection, featuring a Mitsubishi Ki-21 Model 1 Koh from the "Rikugun Koku Shikan Gakko", translated as "Army Air Academy" or "Army Aviation Officer's School". The main school was in Toyooka (present-day Iruma, Saitama Prefecture) but it had many branches as well.

The "Sallys" are all Model 1 Koh with no fuselage hinomaru.
The planes of the school often received their names, written in black hiragana, from cities and various locations.
The "Sally" in the foreground is named "I YO" from here.

The school marking has been traditionally depicted with a kanji ("shi" - as in "SHIkan gakko") in black in a white circle, but this photo proves without any doubt that the kanji was in fact red.

The close-up wing in the photo is from a different type of aircraft. Notice the pitot tube. I would say it's a Mitsubishi Ki-30 "Ann" which is one of the very few, if not only the only, Japanese planes with the pitot on the starboard wing.

Moky asks: Is the dorsal gunner holding a signalling device or a camera (so the two gunners or perhaps the radio operator are taking pictures of each other!)? What do you think? Check the closeup. 

Thank you very much Moky for your contribution.