CJK characters
Chinese is written almost exclusively in Chinese characters. It requires over 3,000 characters for general literacy, but up to 40,000 characters for reasonably complete coverage. Japanese uses fewer characters — general literacy in Japanese can be expected with 1,945 characters. The use of Chinese characters in Korea is becoming increasingly rare, although idiosyncratic use of Chinese characters in proper names requires knowledge (and therefore availability) of many more characters. However, even today, students in South Korea are taught 1,800 characters.
History of printing in East Asia
Given that the Chinese language does not use an alphabet it was usually necessary for a set of type to contain 100,000 or more blocks, which was a substantial investment. Common characters need 20 or more copies, and rarer characters only a single copy. In the case of wood, the characters were either produced in a large block and cut up, or the blocks were cut first and the characters cut afterwards. In either case the size and height of the type had to be carefully controlled to produce pleasing results. To handle the typesetting, Wang Zhen used revolving tables about 2m in diameter in which the characters were divided according to the five tones and the rhyme sections according to the official book of rhymes. The characters were all numbered and one man holding the list called out the number to another who would fetch the type.