I'm a Japanese resident with significant retirement income.
You didn't mention where the income is from, but we are considering taking a pledged asset loan, similar to a HELOC, against our brokerage account before moving to Japan. Putting the loan money into my wife's account so she can bring it to Japan. Then I would just pay it off with my income instead of remitting my income into Japan. Not sure how viable it would be for you as you are currently living in Japan, I'm not even sure how viable it is for us, but since she has not lived in Japan for more that 10-years we can at least avoid a gift tax.