Didn't you say that the Book of Changes has sixteen hexagrams, and the names are all two words? Why do you see fifteen now?

Today's Book of Changes is different from the one just created by Zhou Chaogang, and has been adapted many times. There are different reasons, such as the rulers misinforming people in order to imprison their thoughts, and there are other reasons, such as Cao Xueqin's Dream of Red Mansions, which is not the first edition today.

There are 64 hexagrams in the Book of Changes, but only more than 40 hexagrams are common, and others rarely appear (the one I learned at first was only 54 hexagrams, and the 10 hexagrams were missing). I haven't found any book of changes that records all 64 hexagrams.

The Book of Changes has been looked up to and studied by many people in history, but after all, secrets can't be revealed, and some things can't be understood by the world. I ching suffered two disasters. For the first time, Qin Shihuang burned books to bury Confucianism, and some officials wrote to exhort him that the Book of Changes was only a divination book, leaving a small amount. The second time was a book that was criticized as feudal superstition and nobody read during the Cultural Revolution. Several old people secretly collected them and left a small amount. These two disasters made the original book of changes lost (suppose there are two versions of the book of changes, each version has 63 hexagrams, if there is no one, there will be one less hexagram)

The Book of Changes, the Book of Changes in the Mountain and the Book of Changes in Tibet are also called the Three Changes in the Three Character Classics. It is said that if you get the first copy of one of them, human beings will gain the ability to use supernatural powers. Unfortunately, it has not been found so far, and it is expected to be found in the mausoleum of Qin Shihuang.