Seiryou

It's 1930. Ryuuhei Aoyagi - a former member of the yakuza - receives a military call-up, and is assigned to serve in the Fengtian Freedom Garrison of the Kwantung Army in Manchuria. Ryuuhei was quite popular due to his cheerful disposition, but when his Chinese friend Wan is executed after getting caught in a trap, Ryuuhei rises up in revolt, killing his superior officer! Now having been labeled a felon, he decides to abandon his homeland of Japan and permanently reside in Manchuria. Thus, the notorious "Blue Dragon" of legend is resurrected! Source: Kodansha