A year was divided into 24 solar terms on the traditional Japanese calendar. Toji is the 22nd solar term. It usually begins around December 22nd, the day with the longest night of the year and when the Sun reaches the celestial longitude of 270°. The month that contains Toji is November on the lunar calendar. When the day of Toji falls on the day of Sakutan (the new moon day, namely the 1st day of the month) once every 19 years, it is called Sakutan Toji. If Toji exactly falls on the 1st day of November on the lunar calendar in the 19th year, that proved the correctness of the astronomical calculation and of politics of the time. Therefore Sakutan Toji was cerebrated in ancient Japan.

It is said that if you eat bean porridge or pumpkin and take “yuzu-yu (a Chinese lemmon bath)” on the day of Toji, you will stay in good health without catching cold for the rest of the winter. This is because Toji is a pun for “toji (hot spring cure).” Also “yuzu (Chinese lemmon)” is a pun for “Yuzu ga kiku,” which means “flexible.” So, people took “yuzu-yu” in hope of becoming able to cope with everything flexibly.