Chinese calendar

Chinese calendar
Name	Chinese calendar
Type	Lunisolar
Usedby	Chinese culture
Months	12 or 13
Year	Regnal year, Sexagenary cycle
Epochs	Yellow Emperor, Emperor Yao

Chinese calendar. The traditional lunisolar system is one of the world's oldest chronological records, governing Chinese New Year, agricultural cycles, and Taoist festivals. Its calculations integrate observations of the Sun, the Moon, and the planet Jupiter within a complex framework. The system has undergone numerous reforms, most significantly during the Han dynasty, the Tang dynasty, and under the Jesuit China missions.

History and development

The earliest evidence stems from oracle bone inscriptions from the Shang dynasty, which recorded lunar phases and solar terms. Major institutional reforms were enacted by Emperor Wu of Han, who adopted the Taichu calendar upon advice from astronomers like Luo Xiahong. Subsequent dynasties, including the Yuan dynasty under Kublai Khan, introduced refined systems like the Shoushi calendar crafted by Guo Shoujing. The final imperial system, the Qing's imperial Jesuit-influenced Chongzhen calendar, was superseded by the Gregorian calendar after the Xinhai Revolution.

Structure and components

Its core units are the lunar month, synced to the Moon's phases, and the solar year, aligned to the Sun's position relative to the Celestial equator. Months are numbered and occasionally intercalated, while the year is structured by 24 solar terms like Start of Spring and Winter Solstice. Dating employs the Sexagenary cycle of Heavenly Stems and Earthly Branches, used concurrently with regnal years of emperors such as the Qianlong Emperor. The zodiacal cycle of twelve animal signs, including the Dragon and the Rabbit, is derived from the Earthly Branches.

Astronomical and mathematical basis

Calculations determine the precise moment of the New Moon, marking month start, and the Sun's entry into each solar term, based on the ecliptic longitude. The 19-year Metonic cycle governs the insertion of intercalary months to reconcile lunar and solar cycles. Historical mathematical advancements, like those in the Song dynasty treatise *Dream Pool Essays* by Shen Kuo, contributed to prediction accuracy. The system's Beijing imperial observatory basis shifted to the 120th meridian standard time after the establishment of the Republic of China.

Cultural and social significance

It dictates the timing of major festivals, most notably the Spring Festival celebrations and the Lantern Festival. The Dragon Boat Festival and the Mid-Autumn Festival are also fixed by its dates. It is essential for selecting auspicious days for events like weddings or the tomb-sweeping, often consulting the almanac. Its influence permeates astrological practices, geomancy, and traditional medicine systems documented in the *Bencao Gangmu*.

Regional variations and related calendars

Variants include the Korean, the Vietnamese, and the Ryukyuan calendars, which share the lunisolar structure but differ in festival details. The Japanese calendar used the system until adopting the solar Gregorian calendar during the Meiji Restoration. The Tibetan calendar incorporates elements from the Kalachakra tradition and Indian astronomy. The Hmong and Zhuang ethnic groups maintain distinct agricultural calendars aligned with similar lunar observations.

Modern usage and adaptations

While the Gregorian calendar is official for civil affairs in the People's Republic of China, the traditional system still defines public holidays like the Spring Festival holiday. The Hong Kong and Macau governments issue official almanacs. It remains vital for religious observances in Taoist and folk religious communities, and for cultural events such as the Chiang Mai's Songkran festival in overseas communities. Digital adaptations are widespread, with applications calculating auspicious dates for global users.

Category:Lunisolar calendars Category:Chinese culture