Tian Xi is one of the BaZi Shen Sha (astrological omens), signifying celebration, joy, and childbirth. Tian Xi is complementary to Hong Luan (Red Phoenix). It is determined based on the Year Branch: Zi sees You, Chou sees Shen, Yin sees Wei, Mao sees Wu, Chen sees Si, Si sees Chen, Wu sees Mao, Wei sees Yin, Shen sees Chou, You sees Zi, Xu sees Hai, and Hai sees Xu. A person whose destiny chart contains Tian Xi tends to experience many celebratory events throughout life; years when Tian Xi appears are especially favorable for childbirth.
Determine Tian Xi based on the Year Branch: For Zi-year natives, look for You in any pillar; for Chou-year, Shen; for Yin-year, Wei; for Mao-year, Wu; for Chen-year, Si; for Si-year, Chen; for Wu-year, Mao; for Wei-year, Yin; for Shen-year, Chou; for You-year, Zi; for Xu-year, Hai; for Hai-year, Xu.
A person born in the Year of Zi with You appearing in any of the Four Pillars has Tian Xi entering the destiny chart, indicating abundant celebratory events throughout life.