Ideographic Description Characters

Ideographic Description Characters is a Unicode block containing graphic characters used for describing CJK ideographs. They are used in Ideographic Description Sequences (IDS) to provide a description of an ideograph, in terms of what other ideographs make it up and how they are laid out relative to one another. An IDS provides the reader with a description of an ideograph that cannot be represented properly, usually because it is not encoded in Unicode; rendering systems are not intended to automatically compose the pieces into a complete ideograph, and the descriptions are not standardized.

U+2FF0 to U+2FFB were introduced from GBK; U+2FFC to U+2FFF were devised later and introduced in Unicode 15.1 (2023).

Ideographic Description Sequences are sequences of characters that represent a Chinese character structure as defined by the Unicode standard.

Below are the 16 characters as defined by Unicode in this block:

Two other related ideographic description characters are not encoded in this Unicode block, but of which may be used in ideographic description sequences:

This is the syntax of IDS in EBNF:

IDS := Ideographic | Radical | CJK_Stroke | Private Use | U+FF1F | IDS_UnaryOperator IDS | IDS_BinaryOperator IDS IDS | IDS_TrinaryOperator IDS IDS IDS 
CJK_Stroke := U+31C0 | U+31C1 | ... | U+31E3
IDS_UnaryOperator := U+2FFE | U+2FFF | U+303E
IDS_BinaryOperator := U+2FF0 | U+2FF1 | U+2FF4 | ... | U+2FFD | U+31EF
IDS_TrinaryOperator:= U+2FF2 | U+2FF3

The following Unicode-related documents record the purpose and process of defining specific characters in the Ideographic Description Characters block:

• Chinese character description languages
• Specials (Unicode block)