Is it still a high salary for teaching ESL in Japan?

Yes, the pay in Japan is pretty good. However, the cost of living is also quite high there. You will make enough to live a decent life there, but it can be hard to save much.

In Korea, teachers are well-paid and you are able to save a larger percent of your salary because the cost of living is lower.

In China and southeast Asia, you usually make enough money to live fairly comfortably in the country, but you won't make a lot of money to take home - the cost of living is low, and the pay is correspondingly low.