In Japan, 2,136 are taught through secondary school (the Jōyō kanji); hundreds more are in everyday use.
Due to post-WWII simplifications of Kanji in Japan as well as the post-WWII simplifications of characters in China, the Chinese characters used in Japan today are distinct from those used in China in several respects.
They typically have similar meanings, but often quite different pronunciations.
In other languages, most significantly today in Japanese and sometimes in Korean, characters are used to represent Chinese loanwords, to represent native words independently of the Chinese pronunciation (e.g., kunyomi in Japanese), and as purely phonetic elements based on their pronunciation in the historical variety of Chinese from which they were acquired.
If the Simplified and Traditional Chinese characters are identical, they are written only once.
They have been adapted to write a number of other Asian languages.
In Japan, common characters are written in post-WWII Japan-specific simplified forms (shinjitai), while uncommon characters are written in Japanese traditional forms (kyūjitai), which are virtually identical to Chinese traditional forms.
In South Korea, when Chinese characters are used, they are in traditional form, essentially identical to those used in Taiwan and Hong Kong where the official writing system is traditional Chinese.
They remain a key component of the Japanese writing system (where they are known as kanji) and are occasionally and more so historically, used in the writing of Korean (where they are known as Hanja).
They were formerly used for Vietnamese (in a system known as chữ Nôm) and Zhuang (in a system known as Sawndip). Vietnamese is sometimes also included, making the abbreviation CJKV.