Luban can be said to be the originator of the carpenter industry. His "Lu Ban Shu" was once said to be banned because of these spells. Legend has it that this book not only has a name, but also is called missing a door. Why is it called a leaky door? There are reasons. If someone learns this book, they will become widowed, widowed, lonely, alone and disabled. Of course, this is just one of them. This is the so-called lack of doors.
When a book is spread with such a curse, everyone is afraid to learn it. They are not only afraid that they will become incomplete, but also afraid that someone will use these spells to hurt and curse others. But is this really the case? I don't think so. This is just a legend, there is no exact record. It is reliable to say that this book has only two volumes. The first volume is some precious records of everyone's experience and knowledge in learning craftsman technology, which is very precious and can be learned by everyone.
But the second volume is different. The second volume records a lot of things related to so-called spells, including some methods to protect themselves and some medical knowledge, in order to make people live well. I think this is very good, but it is said to be banned. In fact, there is a little truth, because learning these things is not an easy task, and it is easy to go astray with a little carelessness. Do something that hurts yourself and others.