[Jaydelart]

Fight to defend Japan? Sure, given it's for a cause I believe in.
Enlist in their army? No.

... I'm sorry, the fact that you brought up Anime and Manga in a discussion based around fighting in a war, seems pretty ridiculous to me. I feel to a certain extent that you don't know what you're talking about. War isn't a joke. But, for the sake of the discussion... why would you be willing to enlist in Japan's army... especially to fight China?