Halfwidth Katakana Letter Se

It preserves a narrow text format, not a different sound.

JIS C 6220, established in 1969, added katakana to a one-byte code based on ISO 646. It served constrained printers and terminals, where narrow characters could share fixed-width lines with Latin text. The width was an engineering compromise, not a new Japanese pronunciation.

JIS C 6220 was later renamed JIS X 0201; broader Japanese encodings supplied hiragana and kanji. Unicode preserves the narrow form for compatibility and maps it to ordinary full-width セ. The two read alike but fit different data and layout rules. Microsoft's Japanese IME guide, last updated 2024-06-20, documents F8 for conversion to half-width katakana.

When should I use ｾ instead of セ?

Use ｾ when a field or legacy data calls for half-width kana.

In ordinary Japanese prose, full-width セ is the safer default. ｾ belongs in legacy data, fixed-width text, or a field that explicitly requests half-width kana. Its shape reflects the text system, not tone, dialect, or pronunciation.

As of 2026, official guidance shows both patterns: Tokyo's 018 Support guide requests half-width katakana in an account-name field, while PayPay Bank warns against it in an ordinary kana-name field. Follow the field's width rule; the same syllable may be accepted in one field and rejected in another.