noun
late night to early morning; the small hours
Historical term for the period from midnight until early morning, roughly corresponding to the modern 'small hours'. Not used in everyday modern timekeeping.
後夜は、昔の時刻でいうと丑の刻から寅の刻あたりまでを指す。
後夜 refers to the period from about the hour of the Ox to the hour of the Tiger in the old time system.
noun
around 4am
More specifically, the time around 4am, corresponding to the hour of the Tiger (寅の刻) in the traditional Japanese clock. This is a narrower interpretation of 後夜.
See also: 寅の刻
古典では、後夜は寅の刻、すなわち午前四時ごろとされる。
In classical texts, 後夜 is equated with the hour of the Tiger, i.e., around 4 a.m.