Iftar (fast-breaking) time = sunset. It shifts daily by 1–2 minutes.
For Ramadan 2023 (1444 AH), Tokyo sunset ranged ~6:30 PM – 7:00 PM JST (early to late month).
For any year:
Always confirm with a local source; atmospheric refraction and calculation method (MWL, ISNA, Umm al-Qura, etc.) cause minor variations.