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.

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.

In addition to Japanese, chōonpu are also used in Okinawan writing systems to indicate two morae.