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.
Written Chinese
Various current Chinese characters have been traced back to the late Shang Dynasty about 1200–1050 BC, but the process of creating characters is thought to have begun some centuries earlier. After a period of variation and evolution, Chinese characters were standardized under the Qin Dynasty (221–206 BC). Over the millennia, these characters have evolved into well-developed styles of Chinese calligraphy. As the varieties of Chinese diverged, a situation of diglossia developed, with speakers of mutually unintelligible varieties able to communicate through writing using Classical Chinese. In the early 20th century, Classical Chinese was replaced in this role by written vernacular Chinese, corresponding to the standard spoken language ("Mandarin"). Although most other varieties of Chinese are not written, there are traditions of written Cantonese, written Shanghainese and written Hokkien, among others.