Who fought against Japan in World War II?
It was general policy to use Japanese Americans in the European
theater in units like the famous 442nd RCT, but there were a large
number of Japenese American working as intelligence gatherers and
interrogators in the Pacific. These men were usually commissioned
officers and were kept away from the front, for fear of losing such
a valuble asset due to friendly-fire.
Also there were a small number of Japanese American aviators,
where there was no chance of mistake in indentity. For there
example one Ben Kuroki participated in 28 bombing missions over
mainland Japan and other locations.