Cangjie Input Method

The Cangjie input method (sometimes spelt “Changjie” or “Cang Jei”) is a system by which Chinese characters may be entered into a computer using a standard keyboard. Invented in 1976 by Chu Bong-Foo, the method is named after Cangjie, the man historically credited with the invention of the first Chinese writing system; the name was suggested by Chiang Wei-kuo, then Defence Minister of the Republic of China. Although the input method was initially based upon Traditional Chinese characters, it has since been revamped so that Cangjie and the Simplified Chinese character set can interact.

In filenames and elsewhere, the name Cangjie is sometimes abbreviated as cj.

Unlike pinyin, Cangjie is based on the graphological aspect of the characters: each basic, graphical unit is represented by a basic character component, 24 in all, each mapped to a particular letter key on a standard QWERTY keyboard. An additional, "difficult character" function is mapped to the X key. Within the keystroke-to-character representations, there are four subsections of characters: the Philosophical Set (corresponding to the letters 'A' to 'G' and representing the sun, the moon and the five elements), the Strokes Set (corresponding to the letters 'H' to 'N' and representing the brief and subtle strokes), the Body-Related Set (corresponding to the letters 'O' to 'R' and representing various parts of human anatomy), and the Shapes Set (corresponding to the letters 'S' to 'Y' and representing complex and encompassing character forms).

The basic character components in Cangjie are usually called "radicals"; nevertheless, Cangjie decomposition is not based on traditional Kangxi radicals, nor is it based on standard stroke order; it is in fact a simple geometric decomposition.