The original concept of rare books refers to books that have been strictly collated and have no textual errors. The meaning of "post-Qin" is getting wider and wider, including all kinds of ancient books that were carved earlier and circulated less. Because among the bibliophiles of past dynasties, rare books must be old books, and those that have been copied and engraved closer can only be ordinary books. For example, Ding Bing, a bibliophile in the late Qing Dynasty, stipulated in the Collection of Rare Books: 1, old engraving; 2. Essence; 3, old copy 4, old school. According to the standards of that era, he defined the old edition as the Song and Yuan editions and the refined edition as the Ming edition. According to this classification, with the passage of time, the age limit of rare books in collectors' minds also moves backwards day by day. During the Republic of China, Ming prints gradually entered the ranks of old paintings. After the middle of this century, the woodcuts before Qianlong became scarce, and even no matter how many defects there were, whether they were wrong or not, they were demarcated by age. In fact, real rare books should focus on the contents of books, the scientific research value of ancient books and the value of historical relics.
Engraving is a book printed with engraving. Nothing special.