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.
Chinese characters
Although Chinese characters in Vietnam are now limited to ceremonial uses, they were once in widespread use. Until the early 20th century, Literary Chinese was used in Vietnam for all official and scholarly writing. Around the 13th century the "Nôm" script was developed to record folk literature in the Vietnamese language. The script used Chinese characters to represent both borrowed Sino-Vietnamese vocabulary and native words with similar pronunciation or meaning. In addition thousands of new compound characters were created to write Vietnamese words. This process resulted in a highly complex system that was never mastered by more than 5% of the population. Both Literary Chinese and "Nôm" were replaced in the early 20th century by Vietnamese written with the Latin-based Vietnamese alphabet.