2. There are ten heavenly stems, namely, A, B, C, D, E, J, G, Xin, Ren and Gui.
3. There are twelve earthly branches: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai.
4. Neo-Confucianism, also known as four pillars and eight characters, refers to the time when a person was born, that is, year, month, day and hour.