Kanji is a system of Japanese writing using Chinese characters. The word kanji is the Japanese version of the Chinese word hanzì, which means "Han characters". Kanji or Chinese characters, represent not just sounds but also meanings. Mostly, kanji are used for nouns and the stems of verbs and adjectives. Between 5,000 and 10,000 Chinese characters are used in written Japanese. About half of the Japanese vocabulary comes from Chinese.
In 1981 the Japanese government introduced the jōyō kanji hyō, which includes 1,945 regular characters, plus 166 special characters used only for people's names. All government documents, newspapers, textbooks and other publications for non-specialists use only these kanji. Japanese children are expected to know all of the jōyō kanji by the end of secondary school.
How are kanji to be pronounced?
Kun yomi is the Japanese reading of the character. On yomi is the Chinese reading of the character. Generally, a kanji appearing on its own is given the kun yomi, whereas two or more kanji appearing together, are given the on yomi.
There are some of characters called kokuji (national characters) which were invented in Japan.
Okurigana are kana suffixes following kanji stems in written Japanese words.