Most high budget, well produced documentaries are often about the war in Europe or Pacific. What are some documentaries that you recommend that focuses on other theaters such as Second Sino-Japanese war?
"Nanking" counts as a documentary, even though there are actors reading the diary entries of those who were there. It's pretty compelling.
Check out the documentary series "Battlefield". Its very well produced and focuses on the various battles during WW2 including stuff like the Manchuria campaign and early Japanese invasions.