Source: Noto CJK

U+31B1 Bopomofo Letter Om

U+31B1 was added in Unicode version 3.0 in 1999. It belongs to the block U+31A0 to U+31BF Bopomofo Extended in the U+0000 to U+FFFF Basic Multilingual Plane.

This character is a Other Letter and is mainly used in the Bopomofo script.

The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it is written from left to right. When changing direction it is not mirrored. U+31B1 offers a line break opportunity at its position, except in some numeric contexts.

The Wikipedia has the following information about this codepoint:

Bopomofo, also called Zhuyin Fuhao (注音符號; Zhùyīn fúhào; 'phonetic symbols'), or simply Zhuyin, is a transliteration system for Standard Chinese and other Sinitic languages. It is commonly used in Taiwan. It consists of 37 characters and five tone marks, which together can transcribe all possible sounds in Mandarin Chinese.
Bopomofo was first introduced in China during the 1910s by the Beiyang government, where it was used alongside Wade–Giles, a romanization system which used a modified Latin alphabet. Today, Bopomofo is more common in Taiwan than on the mainland, and is used as a secondary electronic input method for Taiwanese Mandarin, as well as in dictionaries and other non-official documents.

Representations

System	Representation
Nº	12721
UTF-8	E3 86 B1
UTF-16	31 B1
UTF-32	00 00 31 B1
URL-Quoted	%E3%86%B1
HTML hex reference	ㆱ
Wrong windows-1252 Mojibake	ã†±
Encoding: GB18030 (hex bytes)	81 39 B6 31

Elsewhere

Complete Record

Property	Value
Age (age)	3.0 (1999)
Unicode Name (na)	BOPOMOFO LETTER OM
Unicode 1 Name (na1)	—
Block (blk)	Bopomofo Extended
General Category (gc)	Other Letter
Script (sc)	Bopomofo
Bidirectional Category (bc)	Left To Right
Combining Class (ccc)	Not Reordered
Decomposition Type (dt)	none
Decomposition Mapping (dm)	Bopomofo Letter Om
Lowercase (Lower)	✘
Simple Lowercase Mapping (slc)	Bopomofo Letter Om
Lowercase Mapping (lc)	Bopomofo Letter Om
Uppercase (Upper)	✘
Simple Uppercase Mapping (suc)	Bopomofo Letter Om
Uppercase Mapping (uc)	Bopomofo Letter Om
Simple Titlecase Mapping (stc)	Bopomofo Letter Om
Titlecase Mapping (tc)	Bopomofo Letter Om
Case Folding (cf)	Bopomofo Letter Om
ASCII Hex Digit (AHex)	✘
Alphabetic (Alpha)	✔
Bidi Control (Bidi_C)	✘
Bidi Mirrored (Bidi_M)	✘
Composition Exclusion (CE)	✘
Case Ignorable (CI)	✘
Changes When Casefolded (CWCF)	✘
Changes When Casemapped (CWCM)	✘
Changes When NFKC Casefolded (CWKCF)	✘
Changes When Lowercased (CWL)	✘
Changes When Titlecased (CWT)	✘
Changes When Uppercased (CWU)	✘
Cased (Cased)	✘
Full Composition Exclusion (Comp_Ex)	✘
Default Ignorable Code Point (DI)	✘
Dash (Dash)	✘
Deprecated (Dep)	✘
Diacritic (Dia)	✘
Emoji Modifier Base (EBase)	✘
Emoji Component (EComp)	✘
Emoji Modifier (EMod)	✘
Emoji Presentation (EPres)	✘
Emoji (Emoji)	✘
Extender (Ext)	✘
Extended Pictographic (ExtPict)	✘
FC NFKC Closure (FC_NFKC)	Bopomofo Letter Om
Grapheme Cluster Break (GCB)	Any
Grapheme Base (Gr_Base)	✔
Grapheme Extend (Gr_Ext)	✘
Grapheme Link (Gr_Link)	✘
Hex Digit (Hex)	✘
Hyphen (Hyphen)	✘
ID Continue (IDC)	✔
ID Start (IDS)	✔
IDS Binary Operator (IDSB)	✘
IDS Trinary Operator and (IDST)	✘
IDSU (IDSU)	0
ID_Compat_Math_Continue (ID_Compat_Math_Continue)	0
ID_Compat_Math_Start (ID_Compat_Math_Start)	0
Ideographic (Ideo)	✘
InCB (InCB)	None
Indic Mantra Category (InMC)	—
Indic Positional Category (InPC)	NA
Indic Syllabic Category (InSC)	Other
Jamo Short Name (JSN)	—
Join Control (Join_C)	✘
Logical Order Exception (LOE)	✘
Modifier Combining Mark (MCM)	✘
Math (Math)	✘
Noncharacter Code Point (NChar)	✘
NFC Quick Check (NFC_QC)	Yes
NFD Quick Check (NFD_QC)	Yes
NFKC Casefold (NFKC_CF)	Bopomofo Letter Om
NFKC Quick Check (NFKC_QC)	Yes
NFKC_SCF (NFKC_SCF)	Bopomofo Letter Om
NFKD Quick Check (NFKD_QC)	Yes
Other Alphabetic (OAlpha)	✘
Other Default Ignorable Code Point (ODI)	✘
Other Grapheme Extend (OGr_Ext)	✘
Other ID Continue (OIDC)	✘
Other ID Start (OIDS)	✘
Other Lowercase (OLower)	✘
Other Math (OMath)	✘
Other Uppercase (OUpper)	✘
Prepended Concatenation Mark (PCM)	✘
Pattern Syntax (Pat_Syn)	✘
Pattern White Space (Pat_WS)	✘
Quotation Mark (QMark)	✘
Regional Indicator (RI)	✘
Radical (Radical)	✘
Sentence Break (SB)	Other Letter
Soft Dotted (SD)	✘
Sentence Terminal (STerm)	✘
Terminal Punctuation (Term)	✘
Unified Ideograph (UIdeo)	✘
Variation Selector (VS)	✘
Word Break (WB)	Alphabetic Letter
White Space (WSpace)	✘
XID Continue (XIDC)	✔
XID Start (XIDS)	✔
Expands On NFC (XO_NFC)	✘
Expands On NFD (XO_NFD)	✘
Expands On NFKC (XO_NFKC)	✘
Expands On NFKD (XO_NFKD)	✘
Bidi Paired Bracket (bpb)	Bopomofo Letter Om
Bidi Paired Bracket Type (bpt)	None
East Asian Width (ea)	wide
Hangul Syllable Type (hst)	Not Applicable
ISO 10646 Comment (isc)	—
Joining Group (jg)	No_Joining_Group
Joining Type (jt)	Non Joining
Line Break (lb)	Ideographic
Numeric Type (nt)	none
Numeric Value (nv)	not a number
Simple Case Folding (scf)	Bopomofo Letter Om
Script Extension (scx)
Vertical Orientation (vo)	U