Check the Japan 2024 calendar: public holidays, long weekends, and official holiday data — all on one page.
When a Japanese national holiday falls on a Sunday, the next day that is not already a holiday becomes a substitute holiday. In 2026, Constitution Memorial Day (Sunday, 3 May) is observed on Wednesday, 6 May, because 4 and 5 May are already Greenery Day and Children's Day.
Under the Public Holiday Law, a weekday sandwiched between two national holidays becomes a citizens' holiday (kokumin no kyūjitsu). In 2026, 22 September falls between Respect for the Aged Day (21 September) and Autumnal Equinox Day (23 September), creating a five-day Silver Week — the first since 2015.