The Four Corner Method (literal translation) (traditional Chinese: 四角號碼檢字法; simplified Chinese: 四角号码检字法; pinyin: sì jiǎo hào mǎ jiǎn zì fǎ) is a character input method used for encoding Chinese characters either into a computer, or a manual typewriter, using four numerical digits per character. The Four Corner Method is also known as the Four Corner System.
Origin
The Four Corner Method was invented in the 1920s by Wang Yunwu (王云五), the editor in chief at Commercial Press Ltd., China. Its development was based mainly on contributions by the Russian scholar Rosenberg[1][2] in the early 20th century, as well as experiments by Lin Yutang and others[citation needed]. Its original purpose was to aid telegraphers in looking up Chinese telegraph code (CST) numbers in use at that time from long lists of characters. This was mentioned by Wang Yunwu in an introductory pamphlet called Sijiaohaoma Jianzifa in 1926. Introductory essays for this pamphlet were written by Cai Yuanpei and Hu Shi. Hu Shi also composed the following poem Bihuahaoma Ge as a "memory key" to the system:
Traditional Simplified Pinyin
一橫二垂三點捺，
點下帶橫變零頭，
叉四插五方塊六，
七角八八小是九。
一横二垂三点捺，
点下带横变零头，
叉四插五方块六，
七角八八小是九。
Yī héng, èr chuí, sān diǎn, nà;
Diǎn xià dài héng, biàn líng tou;
Cha si, cha wu, fang kuai liu;
Qi jiao, ba ba, xiao shi jiu.
In the 1950s, lexicographers in the People’s Republic of China changed the poem somewhat in order to avoid association with Hu Shih (see the new version, with characters, below). For various reasons, his name was "unmentionable" at the time this was composed.
How it works
The four digits used to encode each character are chosen according to the "shape" of the four corners of each character, i.e. the upper left, upper right, lower left and lower right corners. The shapes can be memorized using a Chinese poem; this version, from the 1958 Xin Sijiaohaoma Cidian, is reworded to avoid the stigma of Hu Shi’s original poem (above). The 1950s version is as follows:
| Traditional |
|
Simplified |
|
Pinyin |
横一垂二三點捺，
叉四插五方框六，
七角八八九是小，
點下有横變零頭。 |
横一垂二三点捺，
叉四插五方框六，
七角八八九是小，
点下有横变零头。 |
Heng yi, chui er, san dian, na;
Cha si, cha wu, fang kuang liu;
Qi jiao, ba ba, jiu shi xiao;
Dian xia you heng, bian ling tou. |
In brief translation: the number 1 represents a horizontal stroke, 2 represents a vertical or diagonal stroke, 3 a dot stroke, 4 two strokes in a cross shape, 5 three or more strokes in which one stroke intersects all others, 6 a box-shape, 7 where a stroke turns a corner, 8 the shape of the Chinese character 八 and its inverted form, and 9 is used for the shape of the Chinese character 小 and its inverted form. Zero is used where there is either nothing in a corner, the part in a corner is already represented by a previous corner, or where a corner has a dot stroke followed by a horizontal stroke.
Several other notes:
- A single stroke can be represented in more than one corner, as is the case with many curly strokes. (eg. the code for 乙 is 1771)
- If the character is fenced by 囗, 門(门), or 鬥, the lower corners are used to denote what is inside the radical, instead of 00 for 囗 or 22 for the others. (eg. the code for 回 is 6060)
There have been scores, maybe hundreds, of such numerical and alpha-numerical systems proposed or popularized (such as Lin Yutang’s "Instant Index", Trindex, Head-tail, Wang An’s Sanjiahaoma, Halpern); some Chinese refer to these generically as "sijiaohaoma" (after the original pamphlet) though this is not correct.
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November 18th, 2008 | Tags: chinese input, chinese input program, chinese input software, Four corner method | Category: Program, Software | Leave a comment
