CJK

In internationalization, CJK is a collective term for the Chinese, Japanese, and Korean languages, all of which use Chinese characters and derivatives (collectively, CJK characters) in their writing systems. Occasionally, Vietnamese is included, making the abbreviation CJKV, since Vietnamese historically used Chinese characters as well.

Collectively, the CJKV characters often include hànzì in Chinese, kanji, kana in Japanese, hanja, hangul in Korean, and Hán tự, chữ Nôm in Vietnamese.

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 Japan can be expected with about 2,000 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.

Other scripts used for these languages, such as bopomofo and the Latin-based pinyin for Chinese, hiragana and katakana for Japanese, and hangul for Korean, are not strictly "CJK characters", although CJK character sets almost invariably include them as necessary for full coverage of the target languages.

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