I have a couple of ex-colleagues in Japan and apparently there are a few expats flying for both the domestic and international airlines in Japan but it is notoriously hard to get a position in the first place and then get through the miriad of obstacles that are imposed.
The JCAB (Civil Aviation Bureau) calls the shots at every turn. Firstly the initial JCAB medical is a marathon in itself - at least two days of tests and checks, including drug testing, stgress ECG, EEC, psychological assessment, psychiatric interviews and a whole range of physical checks. The failure rate is reported to be over 60%.
Then comes the J-ATPL - another huge obstacle course which includes JCAB testing in a Simulator. Attrition rate for those that last the distance is apparently quite high.
Japanese standards are reportedly very high and those that get through are usually very capable and experienced operators.
Most of the jobs in Japan are contract. PARC, Rishworth and IAC are the main companies. PARC reportedly gets the choice jobs and judging from reports the pilots that work for Rishworth and particulalry IAC have problems.
I blieve that living in Japan is not easy because of language and cultural problems. Western pilots are not always welcomed and a re apparently often regarded as cheap foreign labour by their Japanese counterparts despite the fact that the contracts pay quite well.
Far easier to head for the UAE or Europe.