Heart fasting, "fasting" means clearing the heart, and heart fasting refers to inner emptiness and tranquility. It was first published in "Zhuangzi's Human Life": "Only the Tao gathers emptiness, and the emptiness is also fasting." It means: the avenue is empty and quiet, and people's hearts must be empty and quiet to combine the avenue. Therefore, the true fasting method mentioned by Taoism in China is not external vegetarianism, but internal purity, which is the lofty meaning of Taoism in China.
Matters needing attention
Tao Te Ching has the saying that everything is negative and everything is positive. Yin Fu is the opening, and the first chapter is direct.
The method of observing one law is described in Taiping Jing and Shangqing Daqi Jing. The alchemists at that time in later generations mainly inherited one law and one law, and also stole some ideas of one emperor and one woman, but they basically became a mere formality and lost their connotation. Ancient methods are not as simple as modern people think, and each method has its own internal picture, principle and behavior.