Fullwidth Colon

It signals that the next text will explain or fill in the phrase before it.

In Chinese text, a colon follows a statement, speaking verb, label, or heading before an explanation, quotation, or list. Japanese uses it between an item and its details, as in an address or time. In both, it marks structure rather than emotion.

A Japanese text printed in Roman letters in 1591 shows an experiment with European punctuation for readers unfamiliar with Japanese writing. Punctuation spread more widely in Japanese during the Meiji era (1868–1912). Traditional Chinese print generally had little modern punctuation until the early twentieth century, when marks such as the colon became part of standard written Chinese. The exact fullwidth form came later as a typographic and encoding form.

Why is ： wider than :?

Its width aligns it with full-cell text; its punctuation job stays the same.

In East Asian text layouts, many characters occupy a full square cell. The wide colon aligns with that grid and preserves its spacing in mixed-width text and older encodings. The extra width is a layout choice, not a new meaning.

Chinese typesetting also places punctuation dots differently by region. Mainland layouts tend to place the mark near the text edge, while Taiwan and Hong Kong commonly center pause punctuation in the character cell. The reading stays “colon.”

How do I type ：?

Choose full-width punctuation in your input method.

Japanese input methods offer full-width (zenkaku) and half-width choices. Traditional Chinese input methods may offer a width control or symbols menu. The key or menu depends on the input method.

In an otherwise English sentence, switch to direct or half-width input and use :. A stray ： usually looks like a width mismatch or pasted CJK punctuation, not added emphasis.