夏历 XiaLi - Solar Calendar

What is XiaLì (夏曆)?

夏曆 XiàLì The solar, farmers, Chinese, or better known as 萬年曆 WànNiánLì The “Ten Thousand Year Calendar" is a sophisticated astronomical Lunisolar calendar system. Although the evidence indicates that this system predates any remotely assumed Chinese history epoch, it is believed to have been developed during the 夏 Xia Dynasty (2070–1600 BCE); therefore, it is called the (夏曆/夏历 XiaLi) Xia calendar.

The year in this calendar has a division of 24 sectors known as (二十四節氣 ErshiSi JieQi) 24 solar terms; each of the 24 divisions indicates agricultural activities; therefore, (夏历 XiaLi) is also commonly called as (農曆 NóngLì) “Farming calendar”.

The astronomical year of this calendar system begins at midnight on the winter solstice, when the earth is closest to the sun and when the day is shortest around December 21. The calendar year, (元旦 Yuán Dàn) the New Year, begins in the second new moon after the winter solstice.

The months begin at midnight when the new moon phases on the (白經 Bái Jīng) white path, the lunar path on the ecliptic, and (黃經 Huáng Jīng) yellow path, the sun paths on the ecliptic conjunct.

This calendar system in China was used until 1912 and still often mistaken for a pure (陰曆 Yinli) lunar calendar; however, it is a (陰陽曆 Yīn Yáng lì) Yin Yang (Moon/Sun) or, in short, a lunisolar calendar, meaning the months are not based on the lunar phases but the solar terms.

Why is it called the Ten Thousand Year Calendar?

Without getting too much into the details of calendar methods and their individual unit names, the “Ten thousand”, or in numbers, “10.000-year calendar”, is not called as such because the calendar lasts or consists of 10.000 years; rather, it is a reference to one of its units, which is equal to 10.000 years. The largest cycle is 3.600.000 years; this cycle has a division of 360 units, each of which equals 10.000 years.

The smallest unit is known as the (六十花甲 liushi huajia) Sexagenary Cycle or as the (干支 GānZhī) stems-and-branches combination. The alignment of the (十天干 Shi Tian Gan) celestial stems and (十二地支 Shí'èr dìzhī) terrestrial branches in a specific order in six sectors (each of the six sectors consists of 10 stems, or star pointer) will result in 60 combinations; hence, these combinations indicate 60 suns (days) or years.

The sexagenary cycle system initially was used only for days; around the Han dynasty, the year was added, and much later, the month and hours were incorporated.

One sexagenary cycle for years is 60 years,
one cycle for months is 5 years,
one cycle for days is 60 days and
one cycle for the hours is 5 days.

(六十花甲 liushi huajia) Sexagenary Cycle
甲子¹⁹⁸⁴	乙丑¹⁹⁸⁵	丙寅¹⁹⁸⁶	丁卯¹⁹⁸⁷	戊辰¹⁹⁸⁸	已巳¹⁹⁸⁹	庚午¹⁹⁹⁰	辛未¹⁹⁹¹	壬申¹⁹⁹²	癸酉¹⁹⁹³
甲戌¹⁹⁹⁴	乙亥¹⁹⁹⁵	丙子¹⁹⁹⁶	丁丑¹⁹⁹⁷	戊寅¹⁹⁹⁸	已卯¹⁹⁹⁹	庚辰²⁰⁰⁰	辛巳²⁰⁰¹	壬午²⁰⁰²	癸未²⁰⁰³
甲申²⁰⁰⁴	乙酉²⁰⁰⁵	丙戌²⁰⁰⁶	丁亥²⁰⁰⁷	戊子²⁰⁰⁸	已丑²⁰⁰⁹	庚寅²⁰¹⁰	辛卯²⁰¹¹	壬辰²⁰¹²	癸巳²⁰¹³
甲午²⁰¹⁴	乙未²⁰¹⁵	丙申²⁰¹⁶	丁酉²⁰¹⁷	戊戌²⁰¹⁸	已亥²⁰¹⁹	庚子²⁰²⁰	辛丑²⁰²¹	壬寅²⁰²²	癸卯²⁰²³
甲辰²⁰²⁴	乙巳²⁰²⁵	丙午²⁰²⁶	丁未²⁰²⁷	戊申²⁰²⁸	已酉²⁰²⁹	庚戌²⁰³⁰	辛亥²⁰³¹	壬子²⁰³²	癸丑²⁰³³
甲寅²⁰³⁴	乙卯²⁰³⁵	丙辰²⁰³⁶	丁巳²⁰³⁷	戊午²⁰³⁸	已未²⁰³⁹	庚申²⁰⁴⁰	辛酉²⁰⁴¹	壬戌²⁰⁴²	癸亥²⁰⁴³