Hi Rodrigues,
See the link below (Skilled labor, item No.7) and it states that to get a pilot visa in Japan you need to have at least 2,500 hours. I think sponsorship is required as well.
Some years ago, in a small bar in Tokyo, I met some non-Japanese experienced 747 pilots training with JAL so it is possible to get to Japan as a pilot. I think however, you will need to be further up the career ladder before you can get a chance to fly in Japan.
Best of luck.
MOFA: A Guide to Japanese Visas - Appendix 1: Ministerial Ordinance to Provide for Criteria pursuant to Article 7, Paragraph 1 (2) of the Immigration Control and Refugee Recognition Act