The Axis · hearable in two keys at once — a documented double-tonic loop
Axis, Sad Start
Doo-Wop Changes
Royal Road · the J-pop staple — starts off-tonic on 4Δ⁷
↳ reharmAxis, secondary-dominant swap · the 5 becomes 3⁷ — same slots, new gravity↳ reharmDoo-Wop, fifties-sharpened · the 6- goes dominant and starts a chain
Inside moves to graft onIN·12 Secondary Dominant to 6-swap the Axis's 5 for a 3⁷ and the loop gains gravity — the classic pre-chorus upgradeIN·01 Sus Delaysus the 5 at the end of every pre-chorus; release into the chorus downbeatIN·07 Borrowed 4-borrow the 4- on the final pass of the loop — instant last-chorus acheWays outOUT·01 Truck Driver: Up a Half Stepthe final-chorus lift — pop's favorite exit, one fret upOUT·32 Hard Cutcut cold to a new key at the bridge; commit and the ear follows
Target notes, chord by chordLand the 3rd of each chord on its downbeat — it's the note that announces the change. Over the Axis: the key's 7 over the 5 chord, the key's 1 over the 6- (it's that chord's b3). Roots are for the bass; you're painting thirds.How the scale is playedMajor scale or major pentatonic in straight 8ths, built into short repeating hooks — pop melody is a riff you can sing. Two-bar phrases, breathe, repeat with one note changed.Genre theoryThe melody notes 1, 2, 3, 5, 6 carry ninety percent of pop hooks — the pentatonic core. Save the 4 and 7 for tension moments (the sus, the leading tone) and resolve them fast.