The Japanese New Year’s cleaning tradition is called Ōsōji, often written Osoji or Oosouji in English. The term literally means “big cleaning,” and it describes a thorough end-of-year cleaning performed before the New Year begins.
Ōsōji is more than ordinary tidying. Families may dust high surfaces, clean windows, wash floors, clear storage areas, and remove clutter that accumulated during the year. The physical work represents a fresh start and helps prepare the home to welcome the New Year and its good fortune.
The practice is closely associated with ōmisoka, Japanese New Year’s Eve. Traditional preparations historically began around December 13, a date connected with starting New Year preparations and removing soot. Many households aim to finish before January 1, when cleaning may symbolically sweep away the good luck that has just arrived.
Ōsōji is sometimes confused with kadomatsu, which are pine-and-bamboo New Year decorations, or omikuji, the fortune slips found at shrines and temples. Mochi is a rice cake, not a cleaning ritual. The cleaning custom belongs to the broader observance of Oshōgatsu, Japan’s New Year season.