亥いの刻こく

expression, noun

hour of the Boar; around 10 PM

Archaic term from the traditional Japanese temporal system. Refers to the double-hour period associated with the Boar (亥), roughly 9–11 PM or 10 PM–12 AM depending on the era.

• 江え戸ど時じ代だいには、亥いの刻こくは夜よの更ふけた時じ間かん帯たいを指さした。

  In the Edo period, the hour of the Boar referred to the late-night time slot.