Leap month is an important component of the traditional Chinese calendar.
Time is a dimension of human life. To ensure the orderly conduct of production and daily life, as well as to record history, people must measure time and master the methods of measuring and recording it. Different civilizations have different ways of keeping time, resulting in various calendars. The main types are solar calendars, lunar calendars, and lunisolar calendars, with the traditional Chinese calendar being a lunisolar calendar.
“The celestial phenomena are evident, and nothing is greater than the sun and moon.” Regardless of whether it is a solar calendar, lunar calendar, or lunisolar calendar, their foundations are based on the operational laws between the sun and the earth, and the moon and the earth. In simple terms, the solar calendar is based on the time it takes for the earth to orbit the sun (the tropical year, approximately 365 days, 5 hours, 48 minutes, and 46 seconds), also known as the solar calendar, which consists of 12 months. The widely used Gregorian calendar is a type of solar calendar. The solar calendar also has leap years, distinguishing between common years and leap years, with a leap year occurring every four years, and every hundred years having one less leap year, but only adding one day, resulting in 365 days for a common year and 366 days for a leap year. The lunar calendar is based on the time it takes for the moon to orbit the earth (approximately 29 days and 12 hours), consisting of 12 months, totaling 354 or 355 days. The lunisolar calendar is a system that harmonizes the cycles of the sun, earth, and moon. In the traditional Chinese calendar, the time it takes for the earth to complete one rotation is set as one day, and the time when the sun and moon appear to coincide from the earth’s perspective is defined as the beginning of a month, with the month being determined by the lunar phases. Although the length of each year may not be equal, averaging the lengths reveals that a year is approximately equal to the length of a tropical year. This calendar ensures that the full moon occurs in the middle of each month while also allowing the seasonal changes to be observed through the months. The key to achieving this balance of yin and yang lies in the setting of the leap month. The leap month allows people to determine the starting point of the annual cycle and adjust the length of the calendar year to be as close as possible to the tropical year.
“In the sage’s era, the calendar of Yao was maintained, and the leap month was established to correct the timing.” The purpose of setting a leap month in the lunisolar calendar is to “correct the timing.” “Correcting the timing” serves two purposes: first, to determine the beginning of the year; second, to adjust the length of the calendar year to be as close as possible to the tropical year. According to Zhang Jiyou of the Tang Dynasty, the establishment of a leap month is of great significance, “The timing of the heavens is thus established, and the national decrees align with it. Spring brings life, summer promotes growth, and nothing is lost; the east produces while the west completes, who knows the reason? Snow falls in winter, and clouds rise in summer. The evening of autumn brings dew that turns to frost, and the morning of spring brings ice that turns to water.” Therefore, the leap month was highly valued in ancient times.
In China, the practice of setting a leap month to define the four seasons has been recorded for over four thousand years. The “Book of Documents: The Canon of Yao” mentions that Emperor Yao employed capable individuals from the Xi and He families to observe the movements of the sun, moon, and stars, grasp their laws, and teach the people about time. “The emperor said: Consult, you Xi and He. Set the year to 366 days with a leap month to define the four seasons. This will ensure the success of all endeavors.” The essence of this passage is that Emperor Yao said, “You Xi and He, observe the celestial phenomena, and know that a cycle has 366 days, and use the leap month to coordinate the months and years, ensuring that the four seasons do not deviate, thus governing the officials and achieving success in all areas.” It is likely due to this record in the “Book of Documents” that later generations attributed the establishment of the leap month to Emperor Yao and Xi He. For example, Du Zhoushi’s poem “Setting the Leap Month to Define the Seasons” states: “The essence of the original follows the summer path, pushing the calendar as Yao advised,” and Xu Zhi’s poem states: “Accumulating numbers leads to the leap, Xi He holds the old office.”
In the pre-Qin period, leap months were generally placed at the end of the year, hence referred to as the “thirteenth month”; in the early Han Dynasty, October was considered the beginning of the year, September the end, and the leap month was placed after September, called “late September.” Later, with the gradual improvement and incorporation of the twenty-four solar terms into the calendar, months without a middle solar term were designated as leap months.
The “middle solar term” is an important component of the twenty-four solar terms. The twenty-four solar terms are divided into 12 solar terms and 12 middle solar terms, with the solar terms being: Lichun (Beginning of Spring), Jingzhe (Awakening of Insects), Qingming (Clear and Bright), Lixia (Beginning of Summer), Mangzhong (Grain in Ear), Xiaoshu (Minor Heat), Liqiu (Beginning of Autumn), Bailu (White Dew), Hanlu (Cold Dew), Lidong (Beginning of Winter), Daxue (Major Snow), and Xiaohan (Minor Cold); the middle solar terms are: Yushui (Rain Water), Chunfen (Spring Equinox), Guyu (Grain Rain), Xiaoman (Grain Full), Xiazhi (Summer Solstice), Dazhong (Major Heat), Chushu (End of Heat), Qiufen (Autumn Equinox), Shuangjiang (Frost’s Descent), Xiaoxue (Minor Snow), Dongzhi (Winter Solstice), and Dahan (Major Cold). Typically, each month will have one solar term and one middle solar term; for example, in the Dingyou year, June has the solar term Xiaoshu and the middle solar term Dazhong. However, some months may only have a solar term without a middle solar term, and such months become leap months. For instance, this year, the month following June has only one solar term, Liqiu, thus it is called “leap June.”
It is commonly said that “in nineteen years, there are seven leap months” or “in five years, there are two leap months.” Although these are approximate sayings, they reflect the periodic nature of leap months. In fact, the distribution of leap months throughout the year also has a certain regularity; for example, leap months in the first half of the year are significantly more common than in the second half, with leap January, leap September, leap October, leap winter month, and leap December being quite rare. According to estimates, from the year 1645 to 3358, there were 6 leap Januarys and leap winter months, 9 leap September and leap October months, and only 1 leap December, which occurred in the year 3358.
Compared to regular months, leap months are a special time. Around this special time, certain customary activities have formed in the folk culture, which still circulate to this day. One important custom is the giving of leap month shoes.
In many places in China, people believe that years with a leap month are a time of troubles, which is unfavorable for the elderly. In such years, married daughters are expected to give their parents a pair of leap month shoes. When parents wear these leap month shoes, they can avoid misfortune and enjoy health and longevity. The saying goes, “Leap month shoes, leap month wear, leap month elders live a thousand years.” In some areas, it is customary for the shoes to have red decorations, which are believed to ward off evil and bring good fortune.
According to legend, during the Ming Dynasty, a beautiful woman named Li Hua from Yanzhou was married to a county official and became arrogant, neglecting her biological parents and severing ties with her family. Later, Li Hua fell ill, and local doctors were at a loss, so the county official had to invite the famous physician Li Shizhen to treat her.
Li Shizhen prescribed the following: “Quickly make a pair of shoes for your parents, and the illness will be halved; personally give the shoes to the elderly, and the illness will be cured; if you visit your parents every year on the third day of the third month, the sixth day of the sixth month, and the ninth day of the ninth month, this illness will never recur.” He then sang a song called “The Daughter Returns Home on the Third, Sixth, and Ninth”:
“On the third of March, return home to plant trees behind the house;
On the sixth of June, water the young trees during drought;
On the ninth of September, do not forget to fertilize as if pouring oil.”
The county official was delighted with the brilliant prescription. He persuaded his wife to make new shoes and began preparing tree seedlings. On the third of March, Li Hua and her husband brought new shoes and seedlings to visit her parents, and upon seeing her father and mother, she was overcome with emotion and cried, leading to a noticeable improvement in her condition. On the sixth of June and the ninth of September, Li Hua returned with her husband to water and fertilize the seedlings planted in March. As a result, Li Hua’s relationship with her family improved, and her illness was cured. The time when Li Hua made and gifted the shoes was during leap March, hence these shoes became known as “leap month shoes,” and the custom of sending leap month shoes to parents during leap month spread.
In addition to shoes, some places also give other gifts. For example, in Taiwan, married daughters are expected to buy a pair of pig’s feet and noodles for their mothers, usually two front pig’s feet and six bundles of noodles, with red thread and spring flowers tied to the noodles. In the Fuzhou area of Jiangxi, married daughters give their mothers a silver bracelet to pray for their safety. In the Dongshan Township area of Tonggu, it is believed that in leap month years, “heaven adds years and people gain longevity,” so preparing longevity clothes and coffins for the elderly during this time is believed to have a better effect on blessing and extending life. If parents are over sixty, filial children often prepare longevity clothes and coffins at this time to extend their lives.
In some places, it is customary for the daughter’s family to send gifts to the married daughter. For example, in the Yushan area of Jiangxi, the daughter’s family sends umbrellas and fans during leap month, symbolizing that the daughter’s family is a protective umbrella for her, wishing her to have children soon and bring wealth to her husband’s family. In Fujian and Jiangxi, there are also practices of inviting married daughters back to their families for leap month meals. If the parents are no longer alive, the brothers will invite them.
Overall, the customs surrounding leap month emphasize the relationship between married women and their families. As the saying goes, “A married daughter is like spilled water,” in a traditional society where the husband’s family is dominant, once a woman is married, she leaves her hometown where she was born and raised to live in a strange environment, making it rare to be with her biological parents. Therefore, how to manage the relationships between in-laws and maintain emotional connections with her family, especially with her biological parents and siblings, has always been a significant concern in folk society. In China, many traditional festivals have customs for married women to return to their families and visit relatives, which is a social arrangement to address this issue. Sending leap month shoes and sharing leap month meals are part of this. They utilize the special time of leap month to create opportunities for married women to connect with their families, thereby significantly strengthening emotional ties and spiritual support, alleviating the discomfort of married women in their husband’s families, as clearly illustrated in the legend of the origin of leap month shoes. In contemporary times, the relationship between married women and their families has changed, and the practice of sending leap month shoes now expresses the love and filial piety of married daughters towards their parents. It is noteworthy that the story of leap month shoes now occurs not only between married daughters and their families but also between daughters-in-law and their parents-in-law, reflecting the evolution of the leap month shoe custom in contemporary times, which plays a positive role in maintaining harmonious family relationships. Giving leap month shoes, like the custom of giving shoes during the winter solstice, is a warm tradition that deserves to be promoted.