1. Geng metal is the fixed pattern corresponding to the heavenly stems and the five elements, such as: A and Yi - wood; Bing and Ding - fire; Wuji - earth; Geng and Xin - gold; Ren and Gui - water. Geng metal means that all characters with Geng in the horoscope belong to gold.
2. Heavenly Stems is a written sequence symbol in ancient China, which includes: A, B, C, Ding, Wu, Ji, Geng, Xin, Ren and Gui, which are called "Ten Heavenly Stems" ". In ancient China, the Heavenly Stems were mainly used in calendaring, arithmetic, calculation, naming, etc. The ten symbols of the Heavenly Stems can be matched with the five symbols of the Five Elements and the five directions according to their own meanings, among which Jia, Bing, Wu, Geng, and Ren are masculine. , Yi, Ding, Ji, Xin and Gui are negative. In the calendar, celestial stems and earthly branches are often used together, and they cooperate with each other in a fixed order to form a system of stems and branches.