Earthly Branches

The Earthly Branches (Chinese and Japanese: 地支;pinyin: dìzhī;Korean: 지지; or Chinese and Japanese: 十二支;pinyin: shí'èrzhī;Korean: 십이지;literally: "twelve branches") provide one Chinese system for reckoning time.

This system was built from observations of the orbit of Jupiter. Chinese astronomers divided the celestial circle into 12 sections to follow the orbit of 歲星 Suìxīng (Jupiter, the Year Star). Astronomers rounded the orbit of Suixing to 12 years (from 11.86). Suixing was associated with 攝提 Shètí (η Boötis) and sometimes called Sheti.