The time and direction dimension in Chinese Metaphysics Part 1 – 10 Stems (天干) 12 Branches (地枝)

Ancient Chinese astronomers formed the time dimension in relation to its energy pattern, through their observations of the movement of the stars and it is recorded in the Chinese solar calendar.  Chinese solar calendar is used in Chinese Metaphysics mainly for date selection, destiny and forecasting.  The computation of Chinese solar calendar is not based on the sun despite of its name.  Chinese astronomers observed the circumpolar constellations Ursa Major (big dipper) moving around the brightest star shinning in north pole.  The 2 stars which form the bowl are always pointing to the north Polaris star no matter what is the position/orientation of the big dipper.  The big dipper’s handle position which points to different direction help to establish the 4 seasons (spring, summer, fall and winter).  The big dipper is also regarded as the compass of the sky.  Ancient Chinese capital, where imperial astronomer resided,  was located about 41 degree north in latitude which means that the movement of the northern Polaris star and its circumpolar constellations can be observed clearly.  Well I would think that the sky was clearer in ancient day thus enabling them to make very accurate record every night.   Fortunately there were no light pollution and satellites which can mess up the observations back then.

Big dipper orientation changes with each season due to earth orbiting around the sun

During the reign of Hsia emperor about 200 BC,  the calendar was enhanced by taking into consideration of the solar sequence where the seasons are subdivided into 24 nodes  and Feb 4^th is the start of a new spring  (li Chun,  立春).  This calendar is known as Hsia calendar of ten thousand year calendar. 

The solar calendar also take into account  the rotation of the earth and the 5 element  planets (Mercury, Mars, Venus, Jupiter and Saturn)  which gives a movement in time with 5 element energy pattern.  Chinese assigned a heavenly stem and earthly branch which become a pillar to the year, month, day and hour based on the 5 planets with the  sun and moons’ movements visible in the sky.   The 5 elements of wood, fire, earth, metal and water will appear in an orderly binary pattern of yin and yang in the stems.  As a  results there are  10 stems.  There are 12 earthly branches which are coded with animal sign based on Jupiter’s movement.  Jupiter takes 12 years to complete its orbit around the sun, thus the12 earthly branches are represented by 12 animal signs.  The 12 animal signs  are also used to name the month with the 1^st month of the year starting from tiger (yin) month,  day and hour.  A 24 hour day is divided into 12 divisions; therefore each Chinese hour is 2 hours.  The 12 earthly branches have its own direction in the 24 mountains direction applied in Feng Shui.

10 Heavenly stems table 

Wuxing/ 5 elements	Polarity	Chinese Terminology
Wood	Yang	甲(Jia)
	Ying	乙 (Yi)
Fire	Yang	丙 (Bing)
	Ying	丁 (Ding)
Earth	Yang	戊(Wu)
	Ying	己(Ji)
Metal	Yang	庚 (Geng)
	Ying	辛 (Xin)
Water	Yang	壬 (Ren)
	Ying	癸 (Gui)

10 stems

12 earthly branches table

Animal sign	Chinese name	24 direction	Month	Time	Element
Rat	子	N1	Dec 7 – Jan 5	11 pm – 12:59 am	Yang Water
Ox	丑	NE1	Jan 6 - Feb 3	1 am –  2:59 am	Yin Earth
Tiger	寅	NE3	Feb 4 - Mar 5	3 am – 4:59 am	Yang Wood
Rabbit	卯	W2	Mar 6 - Apr 4	5 am – 6:59 am	Yin Wood
Dragon	辰	SE1	Apr 4 - May 5	7 am – 8:59 am	Yang Earth
Snake	巳	SE3	May 6 - Jun 5	9 am – 10:59 am	Yin Fire
Horse	午	S2	Jun 6 - Jul 6	11 am – 12:59 pm	Yang Fire
Goat	未	SW1	Jul 7 - Aug 7	1 pm – 2:59 pm	Yin Earth
Monkey	申	SW3	Aug 8 - Sep 7	3 pm – 4:59 pm	Yang metal
Rooster	酉	E2	Sep 8 - Oct 7	5 pm – 6:59 pm	Yin metal
Dog	戌	NW1	Oct 8 - Nov 6	7 pm – 8:59 pm	Yang earth
Pig	亥	NW3	Nov 7 - Dec 6	9 pm – 10:59 pm	Yin water

12 Branches