It isn't weird for the Balckhawks to have a story in China, they do their work all over the world. China was also struggling against Japan too, so an international, allies aligned force would want to help there. What is weird the turn the story takes.
China has it's own superhero, Wang the Tiger. This is an anomaly in a wartime comic. (Military Comics #25, dated Jan. 1944.) I don't want to spoil too much of what you are about to read, but be ready for a "classic" costume.
Also be ready for the "Ugh, why?" of Chop-chop's caricature. Now, I'm going to add a hopefully big post on Chop-Chop, but this deserves noting here. While all the Chinese people in this story are drawn like normal humans Chop-chop is still a bizarre looking little person.
Line art by John Cassone; Inks by Alex Kotzky
It is possible that Wang the Tiger is a reference to The House of Earth trilogy, a early 1930s series by Pearl S. Buck. The lead character in the first book is Wang the Third/The Tiger.
Interesting too is the this new hero seem to share Military Comics disdain for superpowers, special gadgets, and flashy costumes. Well, I guess that last part is debatable.
Wang the Tiger never shows up again in Quality Comics and to my knowledge DC has never used him either.