Chinese characters are logographs used to write the Chinese languages and others from regions historically influenced by Chinese culture, including Japan, Korea, and Vietnam. They are referred to under different names, depending on where they are used:
- Hanzi (China, Taiwan)
- Kanji (Japan)
- Hanja (North Korea, South Korea)
- Chữ Hán (Vietnam)
Although Chinese characters originated from Chinese Language, each country and language developed their own use of Chinese characters.
Variations in usage
Hanzi
In China and Taiwan, Chinese characters are the only available script to write their languages, and therefore are in heavy use.
Each character represents various meanings and various parts of speech, able to create sentences purely out of Hanzi. It is also noteworthy that the number of readings on each character is fairly limited and each character has only one reading most of the time.
It's also noteworthy that Chinese phonology assigns to every character a syllable composed of an initial, a final, and a tone. Initials and finals 'roughly' corresponds to consonants and vowels, but are distinct in that some initials are combinations of two consonants, and some finals are combinations of a vowel and a consonant.
After Cultural Revolution, China created simplified Chinese Characters (簡體字; 簡体字 in simplified forms) and designated them as the national standard. Since then, China calls traditional Chinese Characters that Taiwan uses as complex characters (繁體字; 繁体字 in simplified forms), while Taiwan calls its traditional characters as orthodox characters (正體字; 正体字 in simplified forms).
Kanji
In Japan, the number of readings on each character is... staggering, to say the least. For more details, refer to Alternate Character Reading and Japanese Writing System
After WWII, Japan simplified relatively fewer Kanjis than China did and called those reformed Kanjis as Shinjitai (新字体; lit. new character forms), while calling old ones as Kyuujitai (旧字体; lit. old character forms). In modern days, Shinjitai practically became the standard in writing, but Kyuujitai is also used occasionally when people want to create an authoritative and trustworthy image, as in business names and store signs.
Hanja
In North Korea and South Korea, each Chinese character is given an identifier composed of its meaning and its sound. This is called Hun-eum (훈음; 訓音 in Hanja).
Contrary to Kanji, Hanja is read only as its sound in Hun-eum, and never as its meaning.
As Classical Chinese is no longer in use, Hanja is only used in professional context for Sino-Korean nouns.
Chữ Hán
In Vietnam, they created thousands of new characters of their own to write native Vietnamese words, on top of the original Chinese characters. These characters unique to Vietnamese are called Chữ Nôm (字喃) and used alongside with the original Chinese Characters in historical text.
However, Vietnam completely abolished Chữ Hán from modern Vietnamese language and now uses Latin-based Vietnamese Alphabet instead.
Do they all share same set of characters?
No. Vietnamese usage of Chinese Characters is a very clear counterexample; Korean and Japanese usages also have culture-specific characters created exclusively for their own uses, although not on the scale comparable to the case of Vietnamese. Those culture-specific characters created for Korean and Japanese usages are respectively called gukja(Hangul: 국자, Hanja: 國字, lit. national characters), and wasei-kanji(和製漢字, lit. Kanjis created by Japanese).
China and Taiwan are no exceptions, as Chinese Characters are the only writing system they have. However, they do not have any official term referring to their culture-specific characters, as their character set is not 'derived' from any pre-existing character set like other cultures. So they interpret their own culture-specific characters as merely outcomes of 'evolution' of Chinese Characters.