1. 高低アクセントとはWhat pitch accent is
Japanese is not a stress language. English marks an accented syllable by making it louder and longer (RE-cord vs re-CORD); Japanese marks it by pitch — the voice sits high or low on each mora, and the word is identified by where the pitch drops.
Two rules do most of the work in standard (Tokyo) Japanese:
- The pitch falls at most once in a word. Once it has dropped, it never climbs back up inside that word.
- The first two moras always differ: if mora 1 is high, mora 2 is low, and vice versa. There is no flat start.
So a word's accent can be described by a single number: the mora after
which the pitch drops. That number is the accent number
(核 downstep position) — 0
means it never drops. onchou stores exactly this number per word, taken
from the Kanjium accent database.
2. 拍（モーラ）Moras, not syllables
Pitch is assigned per mora (拍), not per syllable. A mora is one kana-sized beat:
- Each full kana is one mora: か, さ, ん, っ, ー.
- A small kana (ゃ, ゅ, ょ, ぁ…) attaches to the kana before it: きょ = one mora, not two.
- ん, っ and the long vowel ー each count as a mora of their own.
とうきょう → と・う・きょ・う（4拍）
がっこう → が・っ・こ・う（4拍）
しゃしん → しゃ・し・ん（3拍）
Counting moras correctly matters, because the accent number counts moras. onchou splits readings by this same rule before drawing a diagram or scoring your attempt.
3. 図の読み方Reading the diagrams
A diagram has one dot per mora — high dot = high pitch, low dot = low pitch — plus one hollow trailing dot for whatever comes after the word (a particle like は or が).
Across the word itself these two are identical (low-high-high). They differ only in the trailing dot: 電話が stays high, 男が drops. That is why the hollow dot is drawn at all — without it, two different patterns would look the same.
In the quiz, the red diagram is the target pattern and the blue one is what onchou detected in your recording. A grey, smaller dot means unclear — no voiced pitch was found for that mora (too quiet, or a devoiced/whispered mora).
4. 四つの型The four patterns
Every word falls into one of four types.
平板型 heiban — accent 0
Low first mora, then high to the end — and it stays high onto the following particle. No drop anywhere. The most common pattern, which is why onchou deliberately balances the draw across patterns instead of picking words at random.
頭高型 atamadaka — accent 1
High on the very first mora, then low for the rest. The drop happens immediately after mora 1.
中高型 nakadaka — drop inside the word
Low, then high, then a drop before the last mora. Only possible for words of 3+ moras.
尾高型 odaka — drop after the last mora
High through the final mora, dropping only on what follows. Inside the word this is identical to heiban — you can only hear the difference by adding a particle, so say 男が, not 男 alone.
5. 同音異義語Minimal pairs
Pitch alone distinguishes these. Say each pair out loud with が attached and listen for where — or whether — your voice falls.
| 読み | 語 | 型 | 図 |
|---|---|---|---|
| あめ | 雨 rain | 頭高 (1) | |
| 飴 candy | 平板 (0) | ||
| はし | 箸 chopsticks | 頭高 (1) | |
| 橋 bridge | 尾高 (2) | ||
| 端 edge | 平板 (0) | ||
| かみ | 神 god | 頭高 (1) | |
| 紙 paper | 平板 (0) |
Note that 橋 (odaka) and 端 (heiban) sound the same by themselves — 橋が falls, 端が does not.
6. 練習のしかたHow to practice in onchou
- Look at the target diagram first. Decide where your voice has to drop before you open your mouth.
- Play the reference (▶ Play) and shadow it — imitate immediately, without pausing to analyse.
- Record (button, or the Space key). Speak the word alone, at a normal volume, close to the mic, in a quiet room.
- Compare the two diagrams. The score counts moras that matched; look at which mora went wrong rather than the number.
- Turn on the pitch curve in settings if a mora keeps coming out "unclear" or wrong — the raw F0 trace shows whether you glide instead of stepping, or trail off at the end.
- Start short. Set the practice level to ≤2 moras until atamadaka vs heiban is automatic, then widen it.
Two habits fix most mistakes: keep the pitch flat within a mora instead of sliding, and do not let the last mora sag — a dying voice reads as a drop that was not there.
Accent data from the Kanjium pitch-accent database.