I recall seeing a question on this a while back. I had a consult with a Japanese tax accountant today and thought I would report my findings in case they should be of interest to anyone.
As I expected (though not as i had hoped), superannuation withdrawals—along with IRAs—are treated as ‘public pension’ income under the ‘miscellaneous income (雑所得) category. That means the whole amount (not just capital gains component) is taxed (after the appropriate deductions).
The accountant’s advice was to wait until you can cash everything out and then move to japan, and reinvest. That way you only end up paying capital gains tax on gains achieved after beginning Japanese residency.
The advice was based on the assumption that i would be in Japan on a spouse visa, however, so those who are in Japan on different visas etc. may have different outcomes. He also did say that he wasn’t familiar with the Australian superannuation system, but he seemed quite positive that it would be taxed as income.
So it looks like my plans to relocate will have to wait a few more years, but good to know this now rather than getting a nasty surprise later.
by Hot_Benefit7789