This is a Japan/Manchukuo propaganda poster showing the harmony between the Chinese, Japanese, and Manchurians. I found it on the Hoover website and am using on my East Asian History syllabus for the Spring. (You need a nice Pan-Asian image for that.) I like the image because it is kids, which neatly sidesteps the question of why the Chinese and the Manchurian have abandoned their native loyalties. It’s also hard to envision trying a 6-year old as a war criminal.
The thing that struck me is that Chinese (the one on the right) is holding the old 5-Color flag. This was declared the flag of the Republic after the 1911 revolution. Sun Yat-sen was never happy about this, since he preferred the Shining Sun flag (the current flag of the R.O.C. on Taiwan.) He was turned down on the grounds that Shining Sun was too closely tied to his party and gave the impression that the Republic was a party-state (which is of course why Sun liked it.) In 1921 Sun’s Guangzhou government declared the Shining Sun flag the official flag of the Republic, and after the Northern Expedition this was accepted by everyone.1
Or was it? The Japanese apparently did not. Did they never accept the Shining Sun flag as the symbol of China? Or did they drop this recognition after 1931 or something? Or was the 5-Color flag just a symbol of the Chinese race to them, and they still recognized the Shining Sun as the symbol of the Nanjing state? The imagery is actually sort of odd, since the 5 colors in the Five Color flag were originally held to represent the 5 nationalities of China (Han, Manchu, Mongol, Tibetan and Hui.) Not many Tibetans in Manchukuo, so were the colors in the Manchukuo flag supposed to stand for something other than ethnicity? This site suggests that the four colors on the Manchuguo flag stood for red (bravery), blue (justice), white (purity) and black (determination), but it gives no references.
1Above from Harrison The Making of the Republican Citizen