Chōonpu

"long sound symbol"), also known as chōonkigō (長音記号), onbiki (音引き), bōbiki (棒引き), or Katakana-Hiragana Prolonged Sound Mark by the Unicode Consortium, is a Japanese symbol that indicates a chōon, or a long vowel of two morae in length.

Its form is a horizontal or vertical line in the center of the text with the width of one kanji or kana character.

In horizontal writing it is similar in appearance to, but should not be confused with, the kanji character 一 ("one").

The following table shows the usual hiragana equivalents used to form a long vowel, using the ka-gyō (the ka, ki, ku, ke, ko sequence) as an example.

For example, "or" is usually represented by a long ō (oo or ou) vowel, with the word "torch" becoming トーチ tōchi.