Would it be best to keep it in the US and bring money into Japan as needed?
If so, in a taxable mutual fund account? Seems like a tax reporting nightmare.
Is an IRA advisable for a portion?
A US acquaintance warned me about triple taxation on US income. He was actually moving out of Japan because of it. (he tried to explain it, but it went over my head

Or, would bringing it into Japan to invest be more beneficial? Especially now with the good exchange rate.
(I’m not interested in the hassle of real estate investing).