HR interviews were great and open-minded, especially how young and relatable the interviewer was about being engaged in Japanese culture. However, when you reach to Final Interview, that's where the REAL game begins. So no matter how interested and passionate you genuinely are, the panel seem to be very keen towards your gestures and attitude signs. Be positive as always and never talk back about something since they're testing your behavior.
Lesson learned: Keep calm, prepared, and relaxed. Think positive as always