first day of the fourth month in the lunisolar calendar
Rare historical term referring to a specific date in the old Japanese calendar, around early May in the modern calendar. The name literally means 'cotton-removing first day', associated with the custom of changing from padded winter clothing to lighter garments.
In the old calendar, the first day of the fourth month was considered a marker for the seasonal change of clothing.
Refers to the modern seasonal clothing change (June 1 and October 1), while 綿抜の朔日 is a historical date for the same custom in the lunisolar calendar.
Literally “the first day for removing cotton,” referring to the traditional seasonal removal of cotton padding from winter clothing on the first day of the fourth lunar month.