Which airline in Japan are you looking at?
I had the short course as a 747 FE. Only took six months iinstead of 12 or 13 months.
6 weeks of that was cramming ACME style for the written test.
A pilot also has to take and pass the Radio law test.
Took a JCAB line check from NRT to HNL and somehow passed it back in 1989.
Let me know if I can help out in anyway.
Steve