The Nobleman star (Tian Yi Gui Ren) and the logic behind its calculation

   The Nobleman (Tian Yi Gui Ren  天乙贵人) is an auspicious symbolic star in Four Pillars astrology. It neutralizes the negative influences and is supposed to bring good luck.  Thanks to it, one can easily receive help from others – visible or invisible assistance. 

Table for calculating the star:

year or day of birth - stem	branch
Jia  (Yang Wood)	Wei, Chou (Goat; Ox)
Yi  (Yin Wood)	Shen; Zi (Monkey; Rat)
Bing  (Yang Fire)	Hai; You (Pig; Rooster)
Ding  (Yin Fire)	Hai; You (Pig; Rooster)
Wu  (Yang Earth)	Chou; Wei (Ox; Goat)
Ji  (Yin Earth)	Zi; Shen  (Rat; Monkey)
Geng (Yang Metal)	Chou; Wei (Ox; Goat)
Xin  (Yin Metal)	Yin; Wu  (Tiger; Horse)
Ren  (Yang Water)	Mao; Si  (Rabbit; Snake)
Gui (Yin Water)	Mao; Si  (Rabbit; Snake)

There are many speculations about this symbolic star. After learning that they have Nobleman in the horoscope, many people become highly elated, feeling that they are protected by some sort of angels and higher beings. And if you tell them that they have 2 or 3 Nobleman stars in the chart, they become very excited: “Wow, I have 3 guardian angels!”. This way of thinking easily leads to illusions and misunderstandings. 

The calculation of the Nobleman star is based on the heavenly stems combination. Normally the stems combination is regarded as a positive aspect in Chinese astrology and therefore this symbolic star is given a positive characteristics of assisting the person and removing the obstacles of his way. But there really is nothing that much special in the meaning.

The Qing Dynasty book “Qian Ding Xie Ji Bian Fang Shu”《钦定协纪辨方书》points out: 
“The Nobleman star divides into Yang Nobleman and Yin Nobleman. The calculation of Yang Nobleman starts from Jia Zi (Rat) and is clockwise, while the calculation of Yin Nobleman starts from Shen (Monkey) and is counterclockwise.” 
  For Yang Nobleman, the calculation formula is Jia (Yang Wood) + Zi (Rat). From this base we look at the stems combination and find the branch of the corresponding, i.e. the combined stem:

Jia (Yang Wood) + Zi (Rat) --> Jia (Yang Wood) combines with Ji (Yin Earth), therefore for Ji the Yang Nobleman is in Zi (Rat).

Yi (Yin Wood) + Chou (Ox) --> Yi (Yin Wood) combines with Geng (Yang Metal), therefore for Geng (Yang Metal) the Yang Nobleman is in Chou (Ox).

Bing (Yang Fire) + Yin (Tiger) --> Bing combines with Xin (Yin Metal), therefore for Xin (Yin Metal) the Yang Nobleman is in Yin (Tiger).

Ding (Yin Fire) + Mao (Rabbit) --> Ding combines with Ren (Yang Water), therefore for Ren (Yang Water) the Yang Nobleman is in Mao (Rabbit)..."  

For Yin Nobleman the calculation formula is Jia (Yang Wood) + Shen (Monkey). From this base we look counterclockwise. 
Jia (Yang Wood) + Shen (Monkey) --> Jia (Yang Wood) combines with Ji (Yin Earth), therefore for Ji the Yin Nobleman is in Shen (Monkey). 
Yi (Yin Wood) + Wei (Goat) --> Yi (Yin Wood) combines with Geng (Yang Metal), therefore for Geng (Yang Metal) the Yin Nobleman is in Wei (Goat). 
Bing (Yang Fire) + Wu (Horse) --> Bing combines with Xin (Yin Metal), therefore for Xin (Yin Metal) the Yin Nobleman is in Wu (Horse). 
And so on...