Shogatsugoto-hajime (正月事始め)
Shogatsugoto-hajime (New Year Preparations) means to begin preparations for welcoming the New Year. The day to start preparations was 13th December in the lunar calendar, and is now also 13th December in the solar calendar. In the past there was a custom of going to the mountains on this day to collect wood necessary for New Year including firewood to cook Ozoni (soup containing vegetables and rice cakes) and pine and bamboo for the Kadomatsu decorations.
According to the Senmyoreki lunisolar calendar used until the middle of the Edo period, the 13th of December was always a 'day of the ghost' in the 27 mansions or divisions of Chinese astrology and this day was auspicious for everything except weddings, so it was chosen as a good day to welcome the god of the New Year called Toshigama-sama. In the subsequent calendar reform the date and designation in the 27 mansions disappeared however the date for starting New Year's preparations remained 13th December.