Variation Selector-21

It specifies a registered glyph form for the preceding Han character. VS21 follows a CJK ideograph—a Han character used in Chinese, Japanese, or Korean writing—to make an ideographic variation sequence (IVS). The pair requests a glyph shape, not a different word or reading; “21” is not a style number by itself.

Variation selectors let plain text carry glyph choices that font or style formatting alone may not preserve. Unicode 3.2 documented generic variation selectors as a way to express a glyph choice in plain text. Their standardized forms began at FE00–FE0F; the supplementary selectors later extended this mechanism for ideographic forms.

Because researchers, governments, and publishers need different collections of Han forms, the Ideographic Variation Database (IVD) records independent collections. Its registration history includes Adobe-Japan1 on 2007-12-14, Hanyo-Denshi on 2010-11-14, and Moji_Joho on 2014-05-16. These are registry milestones, not the origin dates of the written forms.

IVD data dated 2026-08-03 lists VS21 in registered pairs in both the Hanyo-Denshi and Moji_Joho collections. The selector number alone cannot identify a requested form; the complete registered pair does.

How do I use VS21 with a CJK character?

Place it directly after the Han character it qualifies. The order is base character, then VS21; keep the two together. Only an exact pair registered in the IVD has a defined ideographic-variation meaning.

An unregistered pairing does not create a new style or meaning. VS21 is not a general-purpose extension that can be attached to any character.

Why is VS21 invisible?

A font or app may ignore VS21, leaving no visible change. The selector has no visible mark of its own. A supported, registered pair can change the glyph; with an unsupported or unregistered pair, the base appears as usual and VS21 is invisible or ignored.