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Long Vowels (長音)
What is a long vowel?
A long vowel (長音, chōon) simply means holding a vowel sound for about twice as long as a short vowel. It's not optional decoration — in Japanese, vowel length changes the meaning of the word, so おばさん (obasan, "aunt") and おばあさん (obaasan, "grandmother") are genuinely different words, not a stylistic variation of the same one.
Long vowels in Hiragana
There's no special long-vowel symbol in hiragana. Instead, you add another vowel character after the syllable, and the rule depends on which vowel it is:
| Vowel | Rule | Example | Romaji |
|---|---|---|---|
| a | add あ | おかあさん (mother) | okaa-san |
| i | add い | おにいさん (brother) | onii-san |
| u | add う | くうき (air) | kuu-ki |
| e | add い (not え, usually) | せんせい (teacher) | sensei (sen-see) |
| o | add う (not お, usually) | おとうさん (father) | otou-san (o-toh-san) |
⚠️ The
e-row ando-row are the tricky ones: the long vowel is usually spelled with an extra い or う, not a repeated え/お. There are a few native-Japanese-word exceptions that do use おお, such as おおきい (ookii, "big") and とおり (toori, "street") — these have to be memorized individually.
Long vowels in Katakana
Katakana has it easy — there's a single dash-like mark, the chōon mark (ー), used for any long vowel regardless of which one it is:
| Word | Romaji | Meaning |
|---|---|---|
| コーヒー | koohii | coffee |
| ビール | biiru | beer |
| スーパー | suupaa | supermarket |
| ケーキ | keeki | cake |
The mark always runs in the direction of the text (horizontal ー in horizontal writing, vertical in vertical writing).
Romanization conventions
Different romanization styles represent long vowels differently. This table shows the same word in each style, so you can recognize them:
| Hiragana | Hepburn (macron) | Hepburn (doubled) | Wāpuro / common input |
|---|---|---|---|
| とうきょう | tōkyō | tookyoo | toukyou |
| おおさか | ōsaka | oosaka | oosaka |
| せんせい | sensei | sensee / sensei | sensei |
- Macron style (ō, ū) is the formal/academic standard (used in dictionaries and textbooks).
- Doubled-letter style (oo, uu) is common in casual romanization and video games.
- This blog generally uses the doubled/plain style (e.g.
juu,sen) for simplicity in the other Japanese notes.
Why it matters: minimal pairs
These word pairs differ only in vowel length, but mean completely different things:
| Short | Long |
|---|---|
| おばさん (obasan, aunt) | おばあさん (obaasan, grandmother) |
| おじさん (ojisan, uncle) | おじいさん (ojiisan, grandfather) |
| ここ (koko, here) | こうこう (koukou, high school) |
| ビル (biru, building) | ビール (biiru, beer) |
| くろ (kuro, black) | くろう (kurou, hardship) |
| とる (toru, to take) | とおる (tooru, to pass through) |
Quick self-test
Cover the right column and try to guess whether the word is a long-vowel word before revealing the reading:
- おかさん → should be おかあさん (missing あ makes it meaningless/incorrect)
- せんせえ → should be せんせい (wrong spelling for the え-row long vowel)
- とけい → とけい (tokei, "clock") — this one has no long vowel at all, careful!