The climate of the four seasons has its own characteristics: warm spring and healthy spring, hot summer and long summer, cool autumn and harvest in autumn, and winter storage and winter storage. But what they have is an inseparable whole and a constantly changing process. Without growth, there will be no collection, and there will be no growth in the second year. It is precisely because of the changes in cold, heat, coolness, growth and collection that life develops and grows normally. On this point, Chinese medicine explains it like this.

For example, Su Wen in Neijing-Four Qi to capture the spirit says: "Yin of the four seasons is the foundation of all things". The so-called "four seasons of yin and yang" refers to the cold, hot and cold changes throughout the year, which are formed by the ups and downs of yin and yang in a year.

Therefore, it is called "four seasons of yin and yang". For example, the solstice in winter is a sun, and the process from spring to summer is the process of yang's birth and yin's extinction, so there is the temperature in spring and the heat in summer; Summer solstice-cloudy, from autumn to winter is the process of yin generating and yang dying, so it is said that autumn is cool and winter is cold. Due to the change of forty yin and yang, there are laws of biological development and growth in Tibet in spring, summer, autumn and winter, so four seasons yin and yang are the foundation of all things. Fundamental, that is, the source of life and death of all things.

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