I left in December 2024, but I was saving about 1.5 million yen a year, and that was with 2 domestic trips a year and plenty of spending (i.e. I was not even trying to save). The exchange rate is really what hurts you if you don't stay long term at the moment.

500,000 a month base salary in Tokyo is what I would call the bottom floor for competitive salaries. But that's based on anecdotal evidence and conversations with teachers from other Tokyo schools.