Halfwidth Katakana Tsu

It is the narrow-width form of ツ, read tsu. The sound stays the same; the difference matters for width, layout, and compatibility with older data formats.

Katakana developed from abbreviated Chinese-character strokes used in early 9th-century Buddhist annotations, where notes had to fit between lines. Its forms settled through practical use by the 12th century, and the modern set was officially fixed in 1900. Katakana later came to write loanwords, names, slang, and sound effects; ﾂ changes the format, not those uses.

The ancestor of つ and ツ is still debated. A 2024 study argues for the old Chinese graph 鬥; other proposals include 川, 州, and 津. These are scholarly reconstructions, not settled origins.

When should I use ﾂ instead of ツ?

Use ﾂ when a field or data format calls for halfwidth kana. In older layout conventions, halfwidth kana fit one display cell beside ASCII characters, while fullwidth Japanese characters took two. Unicode retains both forms for compatibility with existing text and systems.

For ordinary Japanese writing, ツ is the usual choice unless a field specifies halfwidth. On Windows 10/11, Microsoft Japanese IME converts the current input string with F8. As of 2025, Japan Pension Service guidance said e-Gov rejected halfwidth kana; bank forms also set their own field-specific rules.

Why does ﾂﾞ use two characters?

The voiced mark is a separate halfwidth character. In ﾂﾞ, ﾂ and ﾞ are distinct characters. Compatibility normalization can convert the pair to fullwidth ヅ, but some terminals display them in separate cells, which can affect cursor movement and width checks.