Why did Song Zhenzong rename The Deeds of Emperors and Generals in Past Dynasties as Yuan Gui of Bookstore?

After the book was completed, Song Zhenzong personally prefaced it and changed its title to Yuan Gui. "Bookstore" is the source of canon and the treasure house of books. "yuan gui" is a tortoise, a treasure used for divination in ancient times.

The meaning of the name Yuan Gui, a bookstore, is that this book is an ancient turtle with rich reserves, which can be used as a warning for the monarch and his ministers. It is an ancient book learned by monarchs and ministers, that is, the meaning of "the past is not forgotten, and the future is a teacher". The purpose is to "learn the law for the future, so that readers can learn from it."