Yin-Yang
The concept of dividing things into two opposing aspects, such as firmness and yielding, movement and stillness. The Heavenly Stems and Earthly Branches each have yin and yang, and the generating and overcoming relationships of the Five Phases are also divided by yin and yang.
The concept of dividing things into two opposing aspects, such as firmness and yielding, movement and stillness, light and dark.
In Ba Zi (Four Pillars of Destiny), yin-yang determines two things:
- Distinction of the Ten Gods. For the same generating or overcoming relationship, same yin-yang versus different yin-yang results in different Ten Gods: what the Day Master overcomes, if the same yin-yang, is the Indirect Wealth; if different yin-yang, is the Direct Wealth.
- Direction of the Major Cycles (Da Yun). The yin-yang of the Year Stem, combined with gender, determines whether the Major Cycles are arranged forward or backward.
Heavenly Stems: odd positions are yang (甲 Jiǎ, 丙 Bǐng, 戊 Wù, 庚 Gēng, 壬 Rén), even positions are yin (乙 Yǐ, 丁 Dīng, 己 Jǐ, 辛 Xīn, 癸 Guǐ); Earthly Branches similarly: 子 Zǐ, 寅 Yín, 辰 Chén, 午 Wǔ, 申 Shēn, 戌 Xū are yang; 丑 Chǒu, 卯 Mǎo, 巳 Sì, 未 Wèi, 酉 Yǒu, 亥 Hài are yin.