What are Zassetsu?
Zassetsu are uniquely Japanese calendar days that supplement the 24 Solar Terms and Five Seasonal Festivals. They have long been used as seasonal guides closely tied to agriculture and daily life.
Zassetsu were created to account for seasonal changes in Japan's climate that the 24 Solar Terms from China could not fully capture. Deeply connected to agricultural guidelines and seasonal events, they are calendar annotations rooted in Japanese daily life.
Many zassetsu are calculated based on the sun's ecliptic longitude, so they fall on roughly the same dates each year. However, Shanichi is calculated from the sexagenary cycle, and Higan from the vernal and autumnal equinoxes.
List of Zassetsu
| Name | Pronunciation | Period | Description |
|---|---|---|---|
| Setsubun | Setsubun | Around February 3 | The day before the start of each season (Risshun, Rikka, Risshū, Rittō). Most commonly refers to the day before Risshun (start of spring). Known for bean-throwing and ehōmaki customs. Drives away demons (evil spirits) and invites good fortune. |
| Higan (Equinox) | Higan (Equinox) | 3 days before and after the vernal and autumnal equinoxes | A total of 7 days, spanning 3 days before and after the vernal and autumnal equinoxes. A time for visiting ancestors' graves and holding memorial services. On this day the sun rises due east and sets due west, and it is said that the other world (Higan) and this world (Shigan) are closest to each other. |
| Sha-nichi (Earth God Day) | Shanichi (Shrine Day) | The Tsuchinoe day closest to the vernal or autumnal equinox | A day to worship the Ubusuna-gami (local guardian deity). On the spring Sha-nichi (Shunsha), prayers are offered for an abundant harvest before sowing, and on the autumn Sha-nichi (Shūsha), gratitude is given for the harvest. Falls on the Tsuchinoe day closest to the vernal or autumnal equinox. |
| 88th Night (Hachijūhachi-ya) | Hachijūhachi-ya (88th Night) | Around May 2 | The 88th day counting from the start of spring. Drinking new tea picked on this day is said to bring longevity. Known as "the farewell frost of the 88th night," marking when frost is no longer a concern and farm work can begin. |
| Nyūbai (Start of Rainy Season) | Nyūbai (Start of Rainy Season) | Around June 11 | The day when the sun's ecliptic longitude reaches 80°. Marks the start of the rainy season on the calendar. Often differs from the actual onset of the rainy season. Falls on nearly the same date each year since it is based on solar longitude. Used as a guide for rice planting. |
| Hangeshō (Half-Summer) | Hangesho (Half-Summer) | Around July 2 | The day when the sun's ecliptic longitude reaches 100°. An agricultural milestone by which rice planting should be completed. Around this time, the medicinal herb hangeshō (Pinellia ternata) begins to grow. Some regions have customs of eating octopus or mackerel. |
| Doyō (Seasonal Transition) | Doyō (Seasonal Transition) | Approximately 18 days at the end of each season | Approximately 18 days immediately before the start of spring, summer, autumn, and winter. Begins when the sun's ecliptic longitude reaches 27°, 117°, 207°, and 297°. The summer Doyō is particularly well known, with a custom of eating eel on the Day of the Ox. Earthwork is considered inauspicious during Doyō. |
| 210th Day (Nihyaku-tōka) | Nihyaku-tōka (210th Day) | Around September 1 | The 210th day counting from the start of spring. A time when typhoons frequently strike and rice is in bloom, making it an unlucky day for farmers. Along with the 220th day, it is a day to be on guard against storms. |
| 220th Day (Nihyaku-hatsuka) | Nihyaku-hatsuka (220th Day) | Around September 11 | The 220th day counting from the start of spring. Along with the 210th day, it is an unlucky day for typhoons. Particularly coincides with the rice heading period, a time of concern for storm damage. |
Doyō of the Four Seasons
| Season | Solar ecliptic longitude | Period | End |
|---|---|---|---|
| Spring Doyō | 27° | Around April 17 – | The day before the start of summer |
| Summer Doyō | 117° | Around July 20 – | The day before the start of autumn |
| Autumn Doyō | 207° | Around October 20 – | The day before the start of winter |
| Winter Doyō | 297° | Around January 17 – | The day before the start of spring |
During the Doyō period, work involving soil (civil engineering, groundbreaking ceremonies, sowing seeds, etc.) is considered inauspicious. However, on "manichi" (exempt days with no Doyō restrictions), it is considered acceptable to work with soil.