Japan does something similar in the context of things that close after midnight: https://en.wikipedia.org/wiki/Date_and_time_notation_in_Japan#Time https://en.w

Japan does something similar in the context of things that close after midnight: https://en.wikipedia.org/wiki/Date_and_time_notation_in_Japan#Time https://en.wikipedia.org/wiki/Date_and_time_notation_in_Japa... FWIW, the English-speaking world used to switch years on March 25: https://en.wikipedia.org/wiki/Calendar_(New_Style)_Act_1750#New_Year's_Day https://en.wikipedia.org/wiki/Calendar_(New_Style)_Act_1750#... Neither of these are technically things that tzdb can even talk about. They're concerned with civil time, not calendars or other "reckoning" problems.