|Cangjie input method|
Coding of "" (i.e. Cangjie method) in traditional Chinese characters
The Cangjie input method (Tsang-chieh input method, sometimes also Changjie, Cang Jie, or Changjei) 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 (Tsang-chieh), the mythological inventor of the Chinese writing system; the name was suggested by Chiang Wei-kuo, then Defence Minister of Taiwan. 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.
Cangjie is the first Chinese input method that uses the QWERTY keyboard. Other earlier methods use large keyboards with 40 to 2400 keys, except the Four-Corner Method which uses only the number keys. Chu saw that the QWERTY keyboard had become international standard, and believed therefore that Chinese-language input had to be based on it.
Chu Bong-Foo released the patent of Cangjie in 1982 as he thought that it should belong to the Chinese cultural heritage. Therefore, Cangjie has become open source software--free for anyone to use and modify--making Cangjie ubiquitous on every computer system that supports traditional Chinese.
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.
The basic character components in Cangjie are called "radicals" () or "letters" (). There are 24 radicals but 26 keys; the 24 radicals (the basic shapes ?) are associated with roughly 76 auxiliary shapes (?), which in many cases are either rotated or transposed versions of components of the basic shapes. For instance, the letter A (?) can represent either itself, the slightly wider ?, or a 90° rotation of itself. (For a more complete account of the 76-odd transpositions and rotations than the one listed below, see the article on Cangjie entry in Chinese Study Guides.)
|Philosophical group||A||? sun||?, ?, 90° rotated ? (as in ?)|
|B||? moon||the top four strokes of ?, ?, ?, ?, the top and top-left part of ?, ?, and ?, the top-left four strokes of ? and ?, and the top four strokes of ?|
|C||? gold||itself, ?, ?, and the penultimate two strokes of ? and ?|
|D||? wood||itself, the first two strokes of ? and ?, the first two strokes of ? and ?|
|E||? water||?, the last five strokes of ? and ?, ?|
|F||? fire||the shape ?, ?, the first three strokes in ? and ?|
|G||? land||itself, or ? for soldier|
|Stroke group||H||? bamboo||The slant and short slant, the Kangxi radical ?, namely the upper parts in ? and ?|
|I||? dagger axe||The dot, the first three strokes in ? and ?, and the shape ?|
|J||? ten||The cross shape and the shape ?|
|K||? big||The X shape, including ? and the first two strokes of ?, as well as ?|
|L||? centre||The vertical stroke, as well as ? and the first four strokes of ? and ?|
|M||? one||The horizontal stroke, as well as the final stroke of ? and ?, the shape ?, and the shape ?|
|N||? bow||The crossbow and the hook|
|Body parts group||O||? person||The dismemberment, the Kangxi radical ?, the first two strokes of ? and ?, the first two strokes of ?, ?, and ?, and the final two strokes of ?|
|P||? heart||The Kangxi radical ?, the second stroke in ?, the last four strokes in ?, ?, and ?, the shape ?, the shape ?, the penultimate two strokes in ?, and the shape ?|
|Q||? hand||The Kangxi radical ?|
|R||? mouth||The Kangxi radical ?|
|Character shapes group||S||? corpse||?, the first two strokes of ?, the first stroke of ? and ?, the third stroke of ? and ?, the first four strokes of ? and ?|
|T||? twenty||Two vertical strokes connected by a horizontal stroke; the Kangxi radical ? when written as ? (whether the horizontal stroke is connected or broken)|
|U||? mountain||Three-sided enclosure with an opening on the top|
|V||? woman||A hook to the right, a V shape, the last three strokes in ?, ?, and ?|
|W||? field||Itself, as well as any four-sided enclosure with something inside it, including the first two strokes in ? and ?|
|Y||? fortune telling||The ? shape and rotated forms, the shape ?, the first two strokes in ?|
|Collision/Difficult key*||X||?/? collision/difficult||(1) disambiguation of Cangjie code decomposition collisions, (2) code for a "difficult-to-decompose" part|
|Special character key*||Z||(See note)||Auxiliary code used for entering special characters (no meaning on its own). In most cases, this key combined with other keys will produce Chinese punctuations (such as ?,?,? ?,? ?).
Note: Some variants use Z as a collision key instead of X. In those systems, Z has the name "collision" (?) and X has the name "difficult" (?); but the use of Z as a collision key is neither in the original Cangjie nor used in the current mainstream implementations. In other variants, Z may have the name "user-defined" (?) or some other name.
The auxiliary shapes of each Cangjie radical have changed slightly between different versions of the Cangjie method; this is one reason that different versions of the Cangjie method are not completely compatible.
Chu Bong-Foo has provided alternative names for some letters according to their characteristics, for example H (?) is also called ? which means slant. The names form a rhyme for learners to memorize the letters, each group in a line: (The sounds of final characters are given in parentheses)
The typist must be familiar with several decomposition rules ? that define how to analyse a character to arrive at a Cangjie code.
The rules are subject to various principles:
Some forms are always decomposed in the same way, whether the rules say they should be decomposed this way or not. The number of such exceptions is small:
|Version 2||Version 3||Version 5|
|? (door)||? ? (AN)|
|? (eye)||? ? (BU)|
|? (ghost)||? ? (HI)||? ? (HI) or HUI||--|
|? (small table)||? ? (HU)||? ? (HN)|
|? (win)||--||? ? ? ? ? (YRBBN)||? ? ? ? ? (YNBUC)|
|? (tiger [radical])||? ? (YP)|
|? on top of ? (?)||? ? (YR)||? ? ? (YVR)|
|? (fowl)||? ? (OG)|
|? (air [radical])||? ? (OU)||? ? (ON)||? ? ? (OMN)|
|? minus the ?||? ? (VI)|
|? (compete)||? ? (LN)|
|? (mound or city radical)||? ? (NL)|
Some forms cannot be decomposed. They are represented by an X. (Which appears as the ? key on a Cangjie keyboard.)
|Form||Fixed decomposition (v5)|
In the beginning, the Cangjie input method was not a way to produce a character in any character set. It was, instead, an integrated system consisting of the Cangjie input rules and a Cangjie controller board. The controller board contains character generator firmware, which dynamically generates Chinese characters from Cangjie codes when characters are output, using the hi-res graphics mode of an Apple II computer. In the preface of the Cangjie user's manual, Chu Bong-Foo wrote in 1982:
In terms of output: The output and input, in fact, [form] an integrated whole; there is no reason that [they should be] dogmatically separated into two different facilities.... This is in fact necessary....
In this early system, when the user types "yk " (for example) to get the Chinese character ?, the Cangjie codes do not get converted to any character encoding; the actual string "yk " is stored. In a very real sense, the Cangjie code of each character (string of 1 to 5 lowercase letters plus a space) was the encoding of that particular character.
A particular "feature" of this early system is that if you send random lowercase words to the character generator, it will attempt to construct Chinese characters according to the Cangjie decomposition rules, sometimes causing strange, unknown characters to appear. This unusual feature, "automatic generation of characters", is actually described in the manual and is responsible for producing more than 10,000 of the about 15,000 characters that the system can handle. The name Cangjie, evocative of creation of new characters, was actually very apt for this early version of Cangjie.
The presence of the integrated character generator also explains the historical necessity for the existence of the "X" key used for disambiguation of decomposition collisions: because characters are "chosen" when the codes are output, every character that can be displayed must in fact have a unique Cangjie decomposition. It would not make sense--nor would it be practical--for the system to provide a choice of candidate characters when some random text file is displayed; the user would not know which of the candidates are correct.
Cangjie was designed to be an easy-to-use system to help promote the use of Chinese computing; nevertheless, many users find Cangjie to be a difficult method. Many of the perceived difficulties arise from poor instruction.
Enough practice, however, can overcome the above problems. A typist with sufficient practice in Cangjie touch-types, much like one typing English. It is entirely possible for a touch-typist to type at 25 Chinese characters per minute (cpm) or better in Cangjie, yet have difficulty remembering the list of auxiliary shapes or even the decomposition rules. Experienced Cangjie typists can reportedly attain a typing speed between 60 cpm and over 200 cpm.
There are also difficulties arising from current implementations of Cangjie:
Cangjie, however, also has some fundamental problems:
In some situations it cannot be used at all. Cangjie uses all 26 keys in an QWERTY keyboard; it cannot be used to input Chinese on feature phones. For cell phones, zhuyin, 5-stroke (or 9-stroke by Motorola) and the Q9 input method are the current norm because they are designed specifically for use on numeric keypads. Of course, smartphones can and do support Cangjie input by using the touchscreen virtual keyboard.
The Cangjie input method is commonly said to have gone through five generations (commonly referred to as "versions" in English), each of which is slightly incompatible with the others. Currently, version 3 () is the most common; it is the version of Cangjie supported natively by Microsoft Windows. Version 5 (), supported by the Free Cangjie IME and previously the only Cangjie supported by SCIM, represents a significant minority method and supported by iOS.
The early Cangjie system supported by the Zero One card on the Apple II was Version 2; Version 1 was never released.
The Cangjie input method supported on the classic Mac OS is somewhat like Version 3 and somewhat like Version 5.
Version 5, like the original Cangjie input method, was created directly by Chu, the inventor. Chu had hoped that the release of Version 5, originally slated to be Version 6, would bring an end to the "more than ten versions of Cangjie input method" (slightly incompatible versions created by different vendors).
Version 6 has not yet been released to the public, but is being used to create a database which can accurately store every historical Chinese text.
Most modern implementations of Cangjie IMEs provide various convenient features:
Besides the wildcard key, many of these features are very convenient for casual users but unsuitable for touch-typists because they make the Cangjie IME unpredictable.
There have also been various attempts to "simplify" Cangjie one way or another:
Many researchers have discussed ways to decompose Chinese characters into their major components, and have tried to build applications based on the decomposition system. The idea can be referred to as the study of The Genes of Chinese Characters. Cangjie codes certainly offer a basis for such an endeavour. Academia Sinica in Taiwan and Jiaotong University in Shanghai have similar projects as well.
One direct application of the use of decomposed characters is the possibility of computing the similarities in writing Chinese characters, e.g. the Cangjie input method offers a good starting point for this kind of application. By relaxing the limit of five codes for each Chinese character and adopting more detailed Cangjie codes for each character, we can compute visually similar characters. Integrating this with pronunciation information enables computer-assisted learning of Chinese characters.
This is no problem; there are also auxiliary forms to complement the deficiencies of the radicals. The auxiliary forms are variations of the shape of the radicals, [and therefore] easy to remember.
The dictionary appended [to this book] is based on the 4800 standard, commonly used characters as proclaimed by the Ministry of Education. Adding to this the characters that are automatically generated, the number of characters is about 15,000 (using the Kangxi dictionary as a basis).