朔さく日じつ

noun

first day of the lunar month

Refers specifically to the first day of a month in the traditional lunar calendar, not the modern Gregorian calendar.

• 旧きゅう暦れきでは、朔さく日じつは新しん月げつの日ひと重かさなる。

  In the lunar calendar, the first day of the month coincides with the new moon.