The Imperial Japanese AF, like the Imperial Japanese Naval AF, started WW2 equipped with a well-proved mid-1930s heavy bomber. One of the more advanced designs of its era, the Ki-21 shared a lot of features with its G3M naval counterpart. Also like the G3M, the circa two thousand built, served in all the areas where their respective services operated, until the very end.
The Second Sino-Japanese War (1937-45) was the Ki-21’s combat debut. Photo taken during the bombing of Chongqing, China (Sept. 14, 1940).