CJKV Information Processing, 2nd Edition

International Character Set Standards

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e glyphs for ideographs can be compared using a three-dimensional model. e X-axis

(semantic) separates characters by their meaning. e Y-axis (abstract shape) separates

a character on the X-axis into its abstract shapes. Traditional and simplied forms of a

particular ideograph fall into the same X-axis position, but have dierent positions along

the Y-axis. e Z-axis (typeface) separates a character into glyph dierences. Only Z-axis

dierences were merged or unied in Unicode. Table 3-85 provided an example of a Z-axis

dierence. Glyph dierences are usually found when using dierent typefaces to produce

the same character. e same character in dierent languages may also appear dierently

because of locale dierences that have resulted from diversication. Figure 3-1 illustrates

the three-axis model used for comparing the glyphs for ideographs.

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

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Three-axis model for comparing glyphs for ideographsFigure 3-1.

Unfortunately, early standards were inconsistent in their encoding models for ideographs,

and some still are, resulting in separately encoded Z-axis variants.

ere were four sets of national standards from which Unicode’s rst CJK Unied

Ideographs block, the URO, was derived, specically character sets from China, Taiwan,

Japan, and Korea. For example, there were two Japanese ...