U+0451 "ё" Cyrillic Small Letter Io Unicode Character

U+0451 "ё" Cyrillic Small Letter Io is a distinct glyph in the Cyrillic script, representing the letter "yo" in Russian and other languages, where it is used to denote the sound [jo] or [ʲo] after a soft consonant. It is formed by placing a diaeresis, two dots, above the Cyrillic letter "е" (ie), and it appears in positions where stress is implied or to differentiate homographs, such as "всё" (everything) versus "все" (everyone). Historically, its introduction is credited to the Russian historian and writer Nikolai Karamzin in the late 18th century, though its usage remains optional and often contested in modern typography, with many writers preferring "е" in contexts where the pronunciation is clear.

General Properties

Code Point	U+0451
Version Added	1.1
Name	Cyrillic Small Letter Io
Block	Cyrillic
General Category	Lowercase Letter
Canonical Combining Class	Not Reordered
Bidirectional Class	Left To Right
Decomposition Type	Canonical
Decomposition Mapping	"е" U+0435 Cyrillic Small Letter Ie "̈" U+0308 Combining Diaeresis

Encodings

HTML Decimal Encoding	ё
HTML Hex Encoding	ё
UTF-8 Encoding	0xD1 0x91
UTF-16 Encoding	0x0451
UTF-32 Encoding	0x00000451
C/C++/Java Escape	\u0451

Unicode Properties

NFC Quick Check	Yes
NFKC Quick Check	Yes
Numeric Type	None
Numeric Value	NaN
Line Break	Alphabetic
East Asian Width	Ambiguous
Lowercase	Yes
Simple Uppercase Code Point	"Ё" U+0401 Cyrillic Capital Letter Io
Simple Titlecase Code Point	"Ё" U+0401 Cyrillic Capital Letter Io
Uppercase Code Point	"Ё" U+0401 Cyrillic Capital Letter Io
Titlecase Code Point	"Ё" U+0401 Cyrillic Capital Letter Io
Cased	Yes
Changes When Casemapped	Yes
Changes When Titlecased	Yes
Changes When Uppercased	Yes
Script	Cyrillic
Script Extensions	Cyrillic
Indic Syllabic Category	Other
ID Start	Yes
XID Start	Yes
ID Continue	Yes
XID Continue	Yes
Alphabetic	Yes
Vertical Orientation	Rotated
Grapheme Base	Yes
Grapheme Cluster Break	Other
Word Break	Alphabetic letter
Sentence Break	Lower