Click any segment. Hear its chord. The wheel shows you which keys live next to each other — clockwise is up a fifth (C → G → D → A), counter-clockwise is down. Inner ring is the relative minor of each outer key.
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How to read it
Clockwise = up a perfect fifth. C → G → D → A → E → B → F♯ → C♯ → … the right side adds sharps, the left side adds flats.
Adjacent keys (any two next to each other) share six of seven notes. That's why modulating to a neighbor sounds natural.
Inner ring = relative minor. A minor shares all its notes with C major; they're the same key, just centered on a different tonic.
The I-IV-V chord pattern uses three adjacent keys: your home key (I), one clockwise step (V dominant), one counter-clockwise step (IV subdominant). Three-quarters of pop music.
