12 Earthly Branches and

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 歳星 'Suìxīng' (Jupiter, the Year Star). Astronomers rounded the orbit of Suixing to 12 years (from 11.86). Suixing was associated with 'Sheti' (ɳ Böotes) and sometimes called Sheti. http://tripatlas.com/Earthly_branch
The 12 Earthly Branches correspond to the 10 Heavenly Stems. Together they make 22. These have been related to the 22 letters in the Phoenician Alphabet. In other combinations these are used to create a 60 and 120 year cycle.
In Qi Zheng Si Yu:
11 12 1 2 3 4
Zi, Hai, Xu, Yu, Shen, Wei,
Aquarius, Pisces, Aries, Taurus, Gemini, Cancer
T E Ts L S P 22
5 18 12 21 17 5 6 7 8 9 10
Wu Si, Chen, Mao, Yin, Chu
Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn
G R Th M O A 3 20 9 13 !6 1
chou, hai, gong, ji, yin, wu
In Qi Man Dun Jia: San Ji Liu Yi Branch 6 Branch 3 Branch 11 Virgo Gemini Aquarius