Generally that's the starting rate for a college graduate, who I assume would be most likely to be interested in relocating to Japan.

Here's some good numbers at different experience levels: https://www.tokyodev.com/2020/01/07/japan-developer-salaries...

I'll trust his higher end estimate of 16+ years netting you 11 million yen, but I've never seen a job posting anywhere near that even for senior engineers. And even if that is the case, 11 million yen is still far below a FAANG salary with equivalent experience.