Kanji (漢字), literally ("Han characters"), is a Japanese writing system which is derived from Chinese characters (Hanzi). Kanji are used together with three other systems to write modern Japanese:

• Hiragana (平仮名)
• Katakana (片仮名)
• Rōmaji (ローマ字)

TYPES OF KANJI

象形文字 (shōkeimoji)

These characters are sketches of the object they represent. For example, 目 is an eye, 木 is a tree, etc. The current forms of the characters are very different from the original, and it is now hard to see the origin in many of these characters. It is somewhat easier to see in seal script. This kind of character is often called a "pictograph" in English (象形 is also the Japanese word for Egyptian hieroglyphs).

指事文字 (shijimoji)

These are called "logograms", "simple ideographs" and sometimes just "symbols" in English. They are usually simple and represent an abstract concept such as a direction: 上: up/above, 下: down/below, etc.

会意文字 (kaiimoji)

Often called "compound ideographs", or just "ideographs". These are usually a combination of pictographs that combine to present an overall meaning. An example is 峠 (mountain pass) made from 山 (mountain), 上 (up) and 下 (down). Another is 休 (rest) from 人 (person) and 木 (tree).

形声文字 (keiseimoji)

These are called "semasio-phonetic" or "phonetic-ideographic" characters in English. They are by far the largest category, making up about 85% of characters. Typically they are made up of two components, one of which indicates the meaning or semantic context, and the other the pronunciation. (The pronunciation really relates to the original Chinese, and may now only be distantly detectable in the modern Japanese ON reading of the kanji. The same is true of the semantic context, which may have changed over the centuries or in the transition from Japanese to Chinese.)

As examples of this, consider the kanji with the 言 shape: 語, 記, 訳, 説, etc. All are related to word/language/meaning. Similarly kanji with the 雨 (rain) shape (雲, 電, 雷, 雪, 霜, etc.) are almost invariably related to weather. Kanji with the 寺 (temple) shape on the right (詩, 持, 時, 侍, etc.) usually have an ON reading of SHI or JI. Sometimes one can guess the meaning and/or reading simply from the components. However, exceptions do exist -- for example, neither 需 nor 霊 have anything to do with weather (at least in their modern usage), and 待 has an ON reading of TAI.

転注文字 (tenchūmoji)

This group are sometimes called "derivative characters", and is rather vaguely defined. It refers to kanji where the meaning or application has become extended. For example, 楽 is used for 'music' and 'comfort, ease', with different pronunciations in Chinese reflected in Sino-Japanese gaku 'music' and raku 'pleasure'.

仮借文字 (kashamoji)

These are called "phonetic loan characters." Historically, they were the predecessors of the "phonetic-ideographic" characters. For example, 来 in ancient Chinese was originally a pictograph for 'wheat'. Its syllable was homophonous with the verb meaning 'to come' and the character is used for that verb as a result, without any embellishing "meaning" element attached.