Takataka-san
I have spoken to many people about that crucial first flying job and I'm getting mixed reports, some are saying Africa, some are saying CFI in Asia.
Top 20 Career Options as a Pilot » Commercial Pilot » Educational » General Aviation » Pilots » airline transport pilot » Learn to Fly
^ Take a look at this list of options for a pilot a look a little closer to home before taking the leap, in a country like the UK I'm pretty much forced to go east for my first job due to the sheer number of unemployed pilots in the European Union but I understand that there are a lot less pilots in Japan, maybe you could try hunting for these jobs first?
Also, It may not be financially lucrative, but try a local aero club for CFI hours, you may not get paid but you will get CFI experience
Hope to see you in the skies one day.