RetireJapan

Found two great threads on Reddit by the legendary u/starkimpossibility about tokutei kouza and when/why to declare investment income.

https://www.reddit.com/r/JapanFinance/c ... _accounts/
https://www.reddit.com/r/JapanFinance/c ... nt_income/

Great article, I added a link to it from https://retirewiki.jp/wiki/Securities_account_types too