When did Fuxi invent the sixty-four hexagrams?

There are twelve months in a year, about 354 days, and thirteen months and 384 days in a leap year. Fuxi invented sixty-four calendars accordingly. Use one hexagram every day, six hexagrams as one hexagram, and 64 hexagrams for 384 days. The Sunday apparent motion of the sun is from east to south and west, and the annual apparent motion of the sun is from west to south and east. Add an invisible north, and a circular motion is formed. The trajectory of this celestial sphere is what we call the ecliptic. This is the origin of Fuxi's sixty-four hexagrams. From the solstice in winter to the solstice in summer, the sun moves from the Tropic of Cancer to the Tropic of Cancer, showing 32 hexagrams from complex hexagrams to dry hexagrams; From the solstice in summer to the solstice in winter, the sun runs from the Tropic of Cancer to the Tropic of Capricorn, which is represented by the thirty-two hexagrams from Gua Yi to Kun Gua. Therefore, the corresponding complex divination and excessive divination are relative and inverted.

Fuxi's sixty-four hexagrams are derived from the annual apparent motion law of the sun between the north and the south.

The Kun divination in the square diagram is the starting point of the winter solstice, the negative divination is the entry point of the winter solstice, the Thai divination is the sunrise point of the summer solstice, and the dry divination is the entry point of the summer solstice. In other words, Kun Gua is the solstice in winter, Thai Gua is the vernal equinox, dry Gua is the solstice in summer, and negative Gua is the autumnal equinox. Outside the first floor, twenty gossips correspond to twenty-eight nights, seven gossips of modesty, division, promotion, recovery, Ming Yi, pro and Thai correspond to seven nights of black dragon, big beast, need, small beast, big and strong, big and powerful, and seven gossips correspond to seven nights of Xuanwu, northland, shoes, company, no mistake, lawsuit, escape, nothing? Seven hexagrams on each side is seven, and seven times seven is forty-nine, which is a great extension of the year of the return of the lunar calendar. The famous December news divination, such as Pro, Tai, Da Zhuang, Ci, Gan, Ci, Dun, Wu, Guan, Pi and Kun, is in this outer layer, which indicates the rise and fall of Yin and Yang. Twenty-four hexagrams on the second floor correspond to twenty-four solar terms, twelve hexagrams on the third floor correspond to the four seasons in December, and the fourth floor corresponds to the four seasons. It can be seen that Fuxi's sixty-four hexagrams show the law of the apparent movement of the sun and the moon in a highly generalized way, and objectively show the essence and origin of the sixty-four hexagrams.