Corporations can have dual nationality (multinational corporations), but natural persons cannot. :mastoface_with_rolling_eyes: 

Disapproval of dual citizenship “does not violate the Constitution"
Supreme Court dismisses appeal(NHK)
(二重国籍認めないのは“憲法に違反せず” 上告退け確定 最高裁)
https://www3.nhk.or.jp/news/html/20231002/k10014213301000.html