What is the small kana "tsu" used for?

The small kana "tsu" is a hiragana or katakana "tsu" character reduced in size. To see the difference in size using the Japanese fonts in a browser, compare the size of the full-sized hiragana "tsu" in たつと (ta-tsu-to) to the size of a small one in たっと (tatto), or the full-sized katakana "tsu" in タツト (ta-tsu-to) to a small one in タット (tatto).

The small tsu is used to represent a doubled or "geminate" consonant, known as a sokuon (促音) in Japanese. The sokuon is usually represented in rōmaji (romanized Japanese) by a doubled consonant, such as the double t in hatto (ハット), "hat".

For example, "Pocky", a kind of snack, is written in kana as ポッキー, which is ポ, "po", ッ (sokuon), キ, "ki", and ー (chōon) (see What are the names of the Japanese non-kana, non-kanji symbols?). The sokuon is a written way to represent the doubling or lengthening of the k consonant. This kana is romanized as Pokkii. "Wait", or Matte, the te form of the verb matsu (see How does the form work?), is written as 待って, which is 待 (kanji), っ (sokuon), て (te), with the sokuon representing the doubling of the t consonant.

The small tsu is also used at the end of a sentence, to indicate a glottal stop (a sharp or cut-off articulation), which may indicate angry or surprised speech. See What is that small at the end of a sentence?

There are several methods to input a small tsu on a computer, such as xtu, ltu, or ltsu. See How is Japanese input on a computer?

In the International Phonetic Alphabet (IPA), a way of representing speech sounds, the sokuon sound is marked either with a colon-like mark, or a doubled consonant. Here are pairs of words with and without this sound written in IPA:

Word Meaning Romaji IPA representations
来て come kite kʲite
切手 postage stamp kitte kʲitːe; kʲitte; kʲit̚te
あさり clam asari asaɾʲi
あっさり readily assari asːaɾʲi; assaɾʲi

Some of the characters in the above table may not display correctly, in particular the Google Chrome browser is known to have problems displaying the above IPA characters, so if just "kite" and "kitte" appear above, please view with another browser.

In historical kana usage (see What is historical kana usage?), the sokuon sound was often represented by a full-sized tsu kana rather than a small one. Similarly, the Japanese form of Morse code had no way to represent this other than using a full-sized kana.

In all forms of romanization (see What are the systems of romanization of Japanese?) the sokuon is represented by doubling the consonant which follows it. The only exception is the c in chi in the Hepburn system. For this, a preceding sokuon is represented by a "t". For example, Japanese tea is written in kana as まっちゃ (ma-sokuon-chi-small ya). In Hepburn romanization this becomes matcha. The Nippon-shiki (see What is romanization?) and Kunrei-shiki systems both represent this as mattya, thus avoiding one inconsistency.

If you have questions, corrections, or comments, please contact Ben Bullock or use the discussion forum / Privacy

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