Sinkiang, probably in 1940 - 1941, There is no tail stripes (maybe no upperwing insignias), there's other clues that could show this plane belonging to a Russian volunteer unit in late 1939 : aircraft number in Russian style and the fuselage 'art'. the Chinese word 'Sinkiang' means that this aircraft was paid by tuchong (warlord) Sheng Shih-Tsai; who was allied with the soviets and served as a barrage against Moslem rebels infiltration between Sinkiang and Kazakhstan, and was given a little Air Force by Stalin since 1932, which insignia was a shooting star. This small Air Force never made parts of the Chungkuo kunshon, but the High visibility art suggest that the pilot come from this small Air Force... This help to motherland was probably given as a volunteers unit.