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.
Mandarin Chinese
Until the early 20th century, formal writing and even much poetry and fiction was done in Literary Chinese, which was modeled on the classics of the Warring States period and the Han dynasty. Over time, the various spoken varieties diverged greatly from Literary Chinese, which was learned and composed as a special language. Preserved from the sound changes that affected the various spoken varieties, its economy of expression was greatly valued. For example, ("yì," "wing") is unambiguous in written Chinese, but has over 75 homophones in Standard Chinese.