Kanji is the character created in China in ancient times and was introduced to Japan in the 5th or 6th century.
It is used in China, Hong Kong, Taiwan and Japan.
In Korea, it had been used until the middle of the 20th century but only Korean character is mainly used now.
Kanji is a typical logogram in the world, and each character has any meaning and reading.
In a famous old dictionary in China, over 49,000 characters are listed.
Of course, it is impossible for all Kanji users to learn all characters and have an excellent command.
In Japan, a Kanji set with limited characters is organized by Japanese government.
All of them are taught in school and only the characters in the set are used in newspaper, magazine, book, TV in principle.
For 6 years in elementary school (7-12 YO), 1,006 characters are taught.
For 3 years in junior high school (13-15 YO), 1,130 characters are taught.
2,136 characters in all are the compulsory Kanji for Japanese people.
In addition, when we have a baby and give a name, we can use the additional Kanji character set for name.
About 800 characters with lucky meaning are selected, and we can use about 3,000 characters in all for Japanese name.
(When we register the birth of the baby at government office, the name with Kanji character out of above sets is not accepted.)
Japanese people usually use above about 3,000 characters.
But when we learn the history and geography of China, we must know many other Kanji characters.
For the convenience to use such special characters, about 6,300 characters in all are set up in Japanese personal computer.
Kanji is such character set, so if you are a learner in the country without Kanji, I think it is best not to memorize them in earnest.
For reference, I show the Kanji list that the first grade pupil of elementary school must learn.
These 80 characters are the first Kanjis which Japanese children learn in their life.
Kanji in Japanese sentence
Each Kanji has any meaning.
In Chinese, each Kanji has unique pronunciation.
Japan imported the Kanji, and assigned Japanese word to Kanji corresponding to the meaning.
Because Japanese has inflection, Hiragana as the inflected syllables was added after the Kanji.
The verbs and adjectives of Japanese are written by such combination of Kanji and Hiragana.
On the one hand, many Chinese words were also imported, Japan used the Chinese sounds directly.
Therefore, in Japanese, most Kanji characters have both readings of Japanese and Chinese.
In addition, there are some characters that Chinese pronunciation had changed as the centuries roll by.
Some characters have a few Chinese pronunciations in Japanese, so it makes it increasingly difficult for even Chinese learner using Kanji to learn Japanese.
In the 19th century, Japan promoted modernization.
Many intellectuals learned the new Western culture, thought, social system, etc.
They created many new words by combining a few Kanji characters so that Japanese people were able to understand them easily.
Modern China was made after WW2.
The formal name of the country includes the Chinese words such as Renmin (People) and Gongheguo (Republic).
The words were created by Japan in above times, so that is actually the reverse import of Kanji.