Four seasons are suitable for cold and summer-you have to keep pace with the four seasons, "spring grows in summer, autumn harvests in winter". A year is divided into 24 solar terms, with five days as the waiting period, 15 days as one breath, two breaths (30 days) as one section, and 90 days as one season. This is the rhythm of yin and yang in nature, and it is also the biological rhythm of animals and plants. If you don't follow the season, you have to do something out of season, that is, die. Winter is coming, the yang is restrained, and everything is avoided, which is the best health season in a year. As soon as the winter solstice arrived, the ancients began to close the door, the farm work was finished, the grain was put into storage, and people should have a rest. So, I started my practice in March in winter by crossing the valley, meditating, practicing martial arts and reading. Animals hibernate, cats hibernate, and they don't come out if they can.