Intervals
| Interval | Technical name |
|---|---|
| 1 semitone | minor second |
| 2 semitones | major second |
| 3 semitones | minor third |
| 4 semitones | major third |
| 5 semitones | perfect fourth |
| 6 semitones | tritone |
| Interval | Technical name |
|---|---|
| 7 semitones | perfect fifth |
| 8 semitones | minor sixth |
| 9 semitones | major sixth |
| 10 semitones | minor seventh |
| 11 semitones | major seventh |
| 12 semitones | octave |
Basic Chords
- major triads
- minor triads
- diminished triads
- augmented triads
- suspended second chords
- suspended fourth chords
Scales
- major scales
- natural minor scales
- harmonic minor scales
- melodic minor scales
- major pentatonic scales
- minor pentatonic scales
- blues scales
- chromatic scales
Seventh Chords
- dominant seventh chords
- major seventh chords
- minor seventh chords
- minor major seventh chords
- diminished seventh chords
- augmented seventh chords
- half-diminished seventh chords
- augmented major seventh chords
Other Chords
- diminished triads
- augmented triads
- augmented chords
What you can do on this page
This is a reference page rather than a lesson: the interval table, the chord and scale families, and a playable map of every key with its frequency. Click any key in the map to hear it — the notes are laid out exactly as they sit on the keyboard, one semitone apart horizontally and one octave apart vertically.
Use it as a lookup while you learn. If a song page mentions a major third, the interval table tells you it is four semitones. If you are working on the C major scale, the scale list shows you which family it belongs to and where to go next.
How chords, scales and intervals fit together
A scale is a set of notes, a chord is a few notes from that set played together, and an interval is the distance between any two of them. That is the whole hierarchy: learn the twelve intervals and you can build any scale; learn a scale and you can build every chord that belongs to it.
In C major the practical version is short. The scale is C D E F G A B, the three most useful chords are C, F and G, and the shape that builds each of them is a major third stacked on top of a minor third. Everything else on this page is a variation on that idea.
Using the keyboard map below
The two grids at the bottom of the page show the same keyboard twice: once with note names, once with frequencies in hertz. Each row is one octave, and the rows step down from octave 6 to octave 1.
Middle C is the C in the octave 4 row, and it is the reference point every other note is measured from. Press it, then press the same C one row up, and you hear an octave: twelve semitones, the same note name, twice the frequency.
さらに学ぶ
- ピアノ鍵盤ガイド — 鍵の数・配列・名前
- ピアノの弾き方 — 初心者向けの入門ガイド
- 簡単なピアノ曲 — 初心者向けの曲リスト
- 数字譜ツール — 音声やMIDIを数字譜に変換
- Piano chords chart (EN) — all 12 major and minor triads, seventh chords and inversions
- Piano scales (EN) — the major scale formula, all 12 major scales, minor and pentatonic scales
- Piano notes (EN) — note names, octaves and the full keyboard map
- Piano intervals (EN) — every distance named, with the songs that train your ear
- Chord progressions (EN) — the eight loops behind most songs
- How to read sheet music (EN) — clefs, note values, rests and time signatures
- Piano songs with letter notes (EN) — hear the theory in actual pieces