Japanese needs sounds like kya, shu, and cho — consonants that glide through a "y" before the vowel. Rather than invent new symbols, it builds them from kana you already know: take an i-column kana and follow it with a small や, ゆ, or よ. The result is called yōon (拗音, "contracted sound"), and the one idea that makes or breaks it is this: the whole combination is a single mora — one beat — not two.
How yōon is built
Every yōon has the same recipe: an i-column kana (a kana ending in the "i" vowel) plus a small version of や, ゆ, or よ. The small kana drops the "i" of the first kana and swaps in its own vowel, gluing a "y" glide in between.
- き (ki) + small ゃ → きゃ (kya)
- し (shi) + small ゅ → しゅ (shu)
- ち (chi) + small ょ → ちょ (cho)
Only the i-column kana can start a yōon, because only they carry the palatal quality that the "y" glide extends. Here is the full set.
| Base (i-column) |
|
|
|
|---|---|---|---|
| き ki | きゃ kya | きゅ kyu | きょ kyo |
| ぎ gi | ぎゃ gya | ぎゅ gyu | ぎょ gyo |
| し shi | しゃ sha | しゅ shu | しょ sho |
| じ ji | じゃ ja | じゅ ju | じょ jo |
| ち chi | ちゃ cha | ちゅ chu | ちょ cho |
| に ni | にゃ nya | にゅ nyu | にょ nyo |
| ひ hi | ひゃ hya | ひゅ hyu | ひょ hyo |
| び bi | びゃ bya | びゅ byu | びょ byo |
| ぴ pi | ぴゃ pya | ぴゅ pyu | ぴょ pyo |
| み mi | みゃ mya | みゅ myu | みょ myo |
| り ri | りゃ rya | りゅ ryu | りょ ryo |
Notice the sh/j/ch rows behave as you would expect from the base kana: since し is already "shi," しゃ is "sha" (not "shya"), and since ち is "chi," ちょ is "cho." The romanization simply drops the redundant y.
お茶
o cha
tea — 茶 is ちゃ, a single 'cha' beat.
会社
kai sha
company / the office — 社 is しゃ, one 'sha' mora.
宿題
shu ku dai
homework — it opens with しゅ, 'shu.'
旅行
ryo kō
travel / a trip — it opens with りょ, 'ryo.'
The critical point: one mora, not two
This is the single fact that separates learners who understand yōon from those who merely memorized the chart. A yōon is one mora — one beat — even though it is written with two kana. The small や/ゆ/よ does not add a beat; it reshapes the beat that is already there.
You can hear why this matters by comparing a yōon with a genuine two-mora sequence that uses a full-size や/ゆ/よ. The size of the second kana is not cosmetic — it is the difference between one beat and two, and therefore between two different words.
| Full-size (two morae) | Small (one mora, yōon) |
|---|---|
| きよ — ki-yo (2 beats) | きょ — kyo (1 beat) |
| びよ — bi-yo (2 beats) | びょ — byo (1 beat) |
| しゆ — shi-yu (2 beats) | しゅ — shu (1 beat) |
And this is not a theoretical distinction — it produces real minimal pairs, words that differ only in whether the second kana is small:
今日は病院に行きます。
kyō wa byōin ni ikimasu
Today I'm going to the hospital. — きょう (kyō, today) and びょう (byō, in 病院) are both yōon: one beat each.
美容院で髪を切りました。
biyōin de kami o kirimashita
I got my hair cut at the salon. — 美容院 is びよういん (bi-yō-in), NOT びょういん (byō-in, hospital).
Say those two aloud back to back: びょういん (byōin, hospital) is four beats, while びよういん (biyōin, beauty salon) is five — the extra beat is the full-size よ pulling apart into its own mora. A native speaker hears the difference instantly, and sending someone to the wrong building is exactly the kind of error the small kana prevents.
彼は手先が器用だ。
kare wa tesaki ga kiyō da
He's good with his hands. — きよう (器用, ki-yo-u) has a full-size よ, so it's three morae; contrast きょう (kyō, today), two morae with a small ょ.
Orthography: the small kana is smaller and sits lower-left
In print and handwriting, the small ゃ ゅ ょ are physically about half-size and rest at the lower-left of the line, hugging the base kana. The full-size や ゆ よ fill the normal square. This is the same lower-left position where you find the small っ (the sokuon, covered on the small tsu page) — and it is deliberately different from the top-right corner where the voicing marks live, so the eye can keep the two systems apart.
When you handwrite, make the difference obvious: a small kana that is drawn full-size will be read as a separate mora, and you will have written a different word. しゃしん (写真, photo) written as しやしん becomes the non-word "shi-ya-shin."
写真を撮ってもいいですか。
shashin o totte mo ii desu ka
Is it okay if I take a photo? — 写真 is しゃしん; the しゃ is one beat.
次の電車は九時です。
tsugi no densha wa kuji desu
The next train is at nine. — 電車 is でんしゃ (den-sha), with a one-beat しゃ.
Compared to English
English writes ch, sh, and the -u- glide in cute (ky-oot) with strings of letters, and it never counts beats — English syllables stretch and squash freely. Two things are new for you here:
- The glide is one unit. Cho in "chose" and ちょ are the same sound, but where English just spells it, Japanese fuses it into one timed mora. You are not saying "ch-yo"; you are saying a single "cho."
- Timing is meaningful. English tolerates "hospital" said fast or slow. Japanese does not let you blur びょういん into びよういん — the beat count is part of the word's identity. This is why the mora, not the syllable, is the true unit of Japanese rhythm; see mora vs. syllable.
Common mistakes
❌ しゃ pronounced 'shi-ya' (two beats)
Incorrect — しゃ is a single 'sha' mora, one beat.
✅ 会社
kai sha
company — かいしゃ, three beats total: ka-i-sha.
❌ しやしん
Incorrect — a full-size や turns 写真 (shashin) into the non-word 'shi-ya-shin.'
✅ しゃしん
sha shin
photo — the small ゃ keeps it two beats: sha-shin.
❌ びょういん when you mean the salon
Incorrect — びょういん (byōin) is the hospital. The beauty salon is びよういん (biyōin), with a full-size よ.
✅ 美容院
bi yō in
beauty salon — びよういん, five beats, full-size よ.
❌ きょう read as 'ki-yo-u' (three beats)
Incorrect — きょう (today) is two beats, kyo-o; three beats gives you a different word.
✅ 今日
kyō
today — きょう, two beats: the きょ is one mora, followed by a long う.
Key takeaways
- Yōon = an i-column kana
- a small や/ゆ/よ, forming one palatalized sound: きゃ, しゅ, ちょ.
- The whole combination is one mora, one beat — the small kana reshapes the beat, it does not add one.
- Size is meaning: きょ (1 beat) vs きよ (2 beats); びょういん (hospital) vs びよういん (salon).
- Small kana sit lower-left and half-size — never write them full-size, or you spell a different word.
Now practice Japanese
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Japanese→Related Topics
- Dakuten and Handakuten: Voicing MarksN5 — The two small diacritics that expand hiragana — the dakuten (゛) that voices k→g, s→z, t→d, h→b, and the handakuten (゜) that turns the h-row into p — plus the じ/ぢ, ず/づ tangle.
- The Small っ: Geminate Consonants (Sokuon)N5 — How the small っ (sokuon) doubles the following consonant and adds a one-mora silent pause — きて vs きって, がっこう — and why English speakers under-hold it.
- The Mora: Japanese TimingN5 — The mora (拍) is the beat that Japanese is timed by — every kana is one, and long vowels, the small っ, and the moraic ん each add a full beat of their own.