四し更こう

noun

fourth watch of the night (approx. 1am to 3am)

Archaic term from the traditional Chinese timekeeping system, dividing the night into five watches. Used in historical or literary contexts.

• 四し更こうは夜よるの第だい四よんの刻こく限げんで、およそ午ご前ぜん一いち時じから三さん時じまでを指さす。