There are several print types of original East Asian books, such as woodcut, movable type, and manuscripts by hands. Especially in woodcuts and manuscripts by hands is the possibility of errors caused by misprints and hand writing’s errors is higher. The current method of publishing is also the same problem, but at mid-age everything print or copy was done by hand, so the possiblity of error would be high than now. Therefore, proofreading was a very important and difficult task in the East Asian books. In Korea, the importance of proofreading has recently been emphasized, and there have been several discuss at seminars and several specialized books on proofreading have been published. However, there has not been a rigorous national rule, and the issue of Han-character processing in particular has not been discussed. In this article, I discuss in detail the principles of proofreading prevailing in Korea, and hope find develop solutions.