In ancient times, agriculture was the economic mainstay of China and its people, and the purpose of establishing a calendar was to regulate agricultural production. Chinese ancients discovered, through astronomical observation, that during the earth's 12-month orbit around the sun, its changing position gave rise to periodical changes in climate and thus distinctive farming seasons. They subsequently designated 24 positions within the earth's orbit, calling them the 24 Jieqi (24 solar terms).
Each Jieqi was given a name that signified the related meteorological and phenological changes on the earth. For example, Lichun means "the beginning of spring," Jingzhe means "the awakening of insects," and Guyu means "the time to sow wheat." Each of the 12 lunar months encompassed two Jieqi, which were regarded by both the imperial court and farmers as the chronological yardstick through which to plan agricultural production.
