How to type Roman Numeral Nine

Ⅸ lives in the Number Forms block (U+2150-U+218F), fractions and Roman numerals as single characters. Within Unicode it is classified as Nl, a letter-like number. Roman numerals are the familiar example. Its bidirectional class makes it left-to-right.

Its lowercase counterpart is ⅸ (U+2178). They are separate codepoints, so a byte comparison treats them as different characters even though a case-insensitive search does not.

What happens to Ⅸ in a search box

Ⅸ is a compatibility character: Unicode says it can be rewritten as IX, two separate characters. Anything that normalises text to NFKC before comparing it does exactly that, which is why Ⅸ pasted into a search field, a URL slug or a username can come back as IX and match text that never contained Ⅸ at all. NFC, the form this site uses, leaves it alone. Unicode also records its numeric value as 9, so software that asks a character what number it is gets 9 rather than an error.

How Roman Numeral Nine behaves in software

Ⅸ is East Asian Ambiguous: one column in a Western locale and two in a CJK one. That is why a table that lines up on your machine can break on somebody else's, with no change to the text at all. It is a left-to-right character, so it holds that direction even inside a right-to-left paragraph.

Every way to write Roman Numeral Nine

If Ⅸ arrives as â…¨

Its three UTF-8 bytes E2 85 A8 are being read one at a time as Windows-1252. The text is undamaged; the reader has to be told it is UTF-8.