⺀
| ⺀ | |||
| Unicode name | CJK Radical Repeat | ||
|---|---|---|---|
| Code point | U+2E80 | Radical | 3 |
| Block | CJK Radicals Supplement (U+2E80–U+2EFF) | ||
| Character | None — no unified ideograph | ||
| Decomposition | None | ||
| Normalizes under | None — see below | ||
⺀ is a Unicode character at U+2E80, named CJK Radical Repeat. It is not a Chinese character in ordinary use, and it is the first character of the CJK Radicals Supplement block.
Every other character in that block depicts a shape that also exists among the unified ideographs, so each of them has an ordinary character a reader can use instead. ⺀ does not. Unicode records no cross-reference for it, which makes it the one character in either radical block with nothing to point to.
1 What this code point is for✎
The CJK Radicals Supplement block holds the radical shapes that the Kangxi Radicals block leaves out: variant forms, simplified forms, and the shapes a radical takes in one position rather than another. Unicode annotates ⺀ as a variant of Kangxi radical 3, the dot, encoded in the other block as ⼂.
Its purpose is the same as that of the Kangxi Radicals block. A table of radicals is a list of abstract indexing elements rather than a passage of text, and giving those elements their own code points lets a font apply chart-specific shapes and spacing without disturbing how the same glyph is drawn in running prose. The block also serves round-trip compatibility with older East Asian character sets that had made the same separation.
Neither purpose involves writing words. Because ⺀ has no counterpart among the unified ideographs, there is no ordinary character it can stand in for, and no context in running text where it belongs.
2 Normalization behavior✎
⺀ carries no decomposition of any kind. No normalization form — NFC, NFD, NFKC or NFKD — will change it, and none ever will, because normalization is stability-guaranteed and decompositions are not added to existing characters.
For the other 113 undecomposable characters in this block, that permanence is a practical trap. Someone copies a radical glyph out of a chart, and the ordinary character it resembles never matches it again, in any system, indefinitely. ⺀ works differently. There is no ordinary character it could have folded into, so a string containing it will never match anything else, and nothing was lost in the copying.
3 See also✎
4 Further reading✎
- The Unicode Standard, Chapter 18: East Asia — defines the Kangxi Radicals and CJK Radicals Supplement blocks and their intended use
- Unicode Standard Annex #38 — the Unihan database, including the radical-stroke indexing this block supports