Learn every key by name
64 lessons and counting — starting with the letter names of every key (white, sharp, flat, and the full chromatic scale), building through the major, Dorian, and Phrygian scales, every chord triad and 7th chord, chord inversions, and dozens of jazz and gospel color chords along the way (6ths, 9ths, 11ths, 13ths, altered dominants, sus and add chords, quartal and Neapolitan colors, and more) — plus real hymn and gospel song trainers woven in throughout. Every lesson comes with guided playback, and the scale and chord lessons add hands-on MIDI exercises: circle-of-fourths drills, and 5 jazz plus 5 gospel chord progressions in every key. Rootless voicings, improvisation technique, and more are next on the roadmap. Tap the keyboard below to hear it in action.
Choose a lesson
White Keys
The 7 natural letter names — A through G — with guided runs and a flashcard quiz.
Start lesson → Lesson 02Sharp Keys
What a sharp (♯) is, all 7 sharp keys, and where the enharmonic exceptions land.
Start lesson → Lesson 03Flat Keys
What a flat (♭) is, all 7 flat keys, and where the enharmonic exceptions land.
Start lesson → Lesson 04Chromatic & Solfa
All 12 keys, ascending and descending, with movable-do solfa syllables.
Start lesson → Lesson 05Major Scale
The major scale in all 12 keys, plus a short improvisation demo built from real MIDI files.
Start lesson → Lesson 06Dorian Scale
The Dorian mode in all 12 keys, plus a short improvisation demo built from real MIDI files.
Start lesson → Lesson 07Phrygian Scale
The Phrygian mode in all 12 keys, plus a short improvisation demo built from real MIDI files.
Start lesson → Lesson 08Major Chords
How every major triad is built by counting semitones, plus two MIDI exercises: all 12 chords around the circle of fourths, and a I-IV-V-I progression in every key.
Start lesson → Lesson 09Minor Chords
How every minor triad is built by counting semitones, plus two MIDI exercises: all 12 minor chords around the circle of fourths, and a pleasant i-iv-v-i progression in every key.
Start lesson → Lesson 10Augmented Chords
How every augmented triad is built by counting semitones, plus two MIDI exercises: all 12 augmented chords around the circle of fourths, and a pleasant I-I+-vi-IV progression — with just one augmented chord — in every key.
Start lesson → Lesson 11Diminished Chords
How every diminished triad is built by counting semitones, plus two MIDI exercises: all 12 diminished chords around the circle of fourths, and a pleasant I-IV-#ivdim-V progression — with just one diminished chord — in every key.
Start lesson → Lesson 12Power in the Blood — Song Trainer
Play the classic gospel hymn with both hands: the real melody in your right hand, and a new left-hand accompaniment mixing major and minor triads, in every key.
Start lesson → Lesson 13Dominant 7th Chords
How every dominant 7th chord is built by counting semitones (a major triad plus a minor 7th), plus two MIDI exercises: all 12 dominant 7th chords around the circle of fourths, and a classic blues-style I7-IV7-V7-I7 turnaround in every key.
Start lesson → Lesson 14Diminished 7th Chords
How every fully-diminished 7th chord is built from three stacked minor 3rds, plus two MIDI exercises: all 12 diminished 7th chords around the circle of fourths, and a I-V7-vii°7-I cadence showing its dominant-substitute function, in every key.
Start lesson → Lesson 15Minor 7th Chords
How every minor 7th chord is built by counting semitones (a minor triad plus a minor 7th), plus two MIDI exercises: all 12 minor 7th chords around the circle of fourths, and a natural-minor i7-iv7-v7-i7 progression in every key.
Start lesson → Lesson 16Major 7th Chords
How every major 7th chord is built by counting semitones (a major triad plus a major 7th), plus two MIDI exercises: all 12 major 7th chords around the circle of fourths, and a classic jazz/gospel Imaj7-vi7-ii7-V7 turnaround in every key.
Start lesson → Lesson 17Half-Diminished 7th Chords
How every half-diminished 7th (m7♭5) chord is built from a diminished triad plus a minor 7th, plus two MIDI exercises: all 12 half-diminished 7th chords around the circle of fourths, and a I-V7-viiø7-I cadence showing its diatonic leading-tone role, in every key.
Start lesson → Lesson 18His Eye Is on the Sparrow — Song Trainer
Play the classic gospel hymn exactly as originally arranged — real melody, real accompaniment, unaltered — including all five 7th-chord colors taught in Lessons 13-17, in every key.
Start lesson → Lesson 206th Chords
How every 6th chord is built by counting semitones (a major triad plus a major 6th), plus three MIDI exercises: all 12 6th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring the 6th chord, in every key.
Start lesson → Lesson 21Minor 6th Chords
How every minor 6th chord is built by counting semitones (a minor triad plus a major 6th), plus three MIDI exercises: all 12 minor 6th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring the minor 6th chord, in every key.
Start lesson → Lesson 22Chord Inversions
What inversions are, the different types, and how to build one for every chord type taught so far — then 5 jazz and 5 gospel chord progressions where you choose the inversion and play in every key.
Start lesson → Lesson 23Augmented 7th Chords
Also known as 7♯5, +7, C+7, C7+, or augmented dominant seventh — how every augmented 7th chord is built by counting semitones (a dominant 7th with a raised 5th), plus three MIDI exercises: all 12 augmented 7th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this altered dominant, in every key.
Start lesson → Lesson 24Major 7th ♭5 Chords
Also known as maj7♭5, M7♭5, or Δ7♭5 — how every major 7th flat 5 chord is built by counting semitones (a major 7th chord with a lowered 5th), plus three MIDI exercises: all 12 maj7♭5 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this unsettled, floating color, in every key.
Start lesson → Lesson 25Major 7th ♯11 Chords
Also known as maj7♯11, M7♯11, or Δ7♯11 — how every major 7th sharp 11 chord is built by counting semitones (a major 7th chord plus a raised 11th on top), plus three MIDI exercises: all 12 maj7♯11 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this bright, "Lydian" color, in every key.
Start lesson → Lesson 26Add9 Chords
How every add9 chord is built by counting semitones (a major triad plus a 9th on top, with no 7th of any kind), plus three MIDI exercises: all 12 add9 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this bright, wide-open, "at rest" color, in every key.
Start lesson → Lesson 27Sus2 Chords
How every sus2 chord is built by counting semitones (a plain fifth with the 3rd replaced by a major 2nd, so the chord is neither major nor minor), plus three MIDI exercises: all 12 sus2 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this open, unresolved color, in every key.
Start lesson → Lesson 28Sus4 Chords
How every sus4 chord is built by counting semitones (a plain fifth with the 3rd replaced by a perfect 4th, the mirror image of the sus2 chord), plus three MIDI exercises: all 12 sus4 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring its taut, leaning color, in every key.
Start lesson → Lesson 29Dominant 7sus4 Chords
How every dominant 7sus4 chord is built by counting semitones (a sus4 chord with a minor 7th stacked on top, the suspended cousin of a plain dominant 7th), plus three MIDI exercises: all 12 7sus4 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring its softened, lingering pull, in every key.
Start lesson → Lesson 306/9 Chords
How every 6/9 chord is built by counting semitones (a plain 6th chord with a 9th stacked on top, and no 7th of any kind), plus three MIDI exercises: all 12 6/9 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this rich, fully "at rest" color, in every key.
Start lesson → Lesson 32Dominant 9th Chords
How every 9 chord is built by counting semitones (a plain dominant 7th chord (Lesson 13) with a 9th stacked on top), plus three MIDI exercises: all 12 Dominant 9th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 33Dominant 11th Chords
How every 11 chord is built by counting semitones (a dominant 9th chord (Lesson 32) with an 11th stacked on top), plus three MIDI exercises: all 12 Dominant 11th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 34Dominant 13th Chords
How every 13 chord is built by counting semitones (a dominant 11th chord (Lesson 33) with a 13th stacked on top — the fullest possible dominant chord), plus three MIDI exercises: all 12 Dominant 13th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 35Dominant 7♭9 Chords
How every 7♭9 chord is built by counting semitones (a plain dominant 7th chord (Lesson 13) with its 9th lowered a semitone instead of left natural), plus three MIDI exercises: all 12 Dominant 7♭9 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 36Dominant 7♯9 Chords
How every 7♯9 chord is built by counting semitones (a plain dominant 7th chord (Lesson 13) with a raised 9th on top — nicknamed the "Hendrix chord"), plus three MIDI exercises: all 12 Dominant 7♯9 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 37Dominant 7♭5 Chords
How every 7♭5 chord is built by counting semitones (a plain dominant 7th chord (Lesson 13) with its 5th lowered a semitone), plus three MIDI exercises: all 12 Dominant 7♭5 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 38Dominant 7♯11 Chords
How every 7♯11 chord is built by counting semitones (a plain dominant 7th chord (Lesson 13) with a raised 11th on top — the Lydian dominant color), plus three MIDI exercises: all 12 Dominant 7♯11 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 39Dominant 7♭13 Chords
How every 7♭13 chord is built by counting semitones (a plain dominant 7th chord (Lesson 13) with a lowered 13th on top — a darker altered-dominant color), plus three MIDI exercises: all 12 Dominant 7♭13 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 40Dominant 9♯11 Chords
How every 9♯11 chord is built by counting semitones (a dominant 9th chord (Lesson 32) with a raised 11th stacked on top — also called the Lydian dominant 9), plus three MIDI exercises: all 12 Dominant 9♯11 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 41Altered Dominant Chords
How every 7alt chord is built by counting semitones (an umbrella name for any dominant 7th chord voiced with altered upper tones (some mix of ♭5, ♯5, ♭9, ♯9) — this trainer voices the common ♯5/♯9 combination), plus three MIDI exercises: all 12 Altered Dominant chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions featuring this color, in every key.
Start lesson → Lesson 42Minor 9th Chords
How every m9 chord is built by counting semitones (a minor 7th chord (Lesson 15) with a 9th stacked on top), plus three MIDI exercises: all 12 minor 9th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 43Minor 11th Chords
How every m11 chord is built by counting semitones (a minor 9th chord (Lesson 42) with an 11th stacked on top), plus three MIDI exercises: all 12 minor 11th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 44Minor 13th Chords
How every m13 chord is built by counting semitones (a minor 11th chord (Lesson 43) with a 13th stacked on top — the fullest stock minor 7th-family chord), plus three MIDI exercises: all 12 minor 13th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 45Minor 6/9 Chords
How every m6/9 chord is built by counting semitones (a minor 6th chord (Lesson 21) with a 9th stacked on top, and no 7th of any kind), plus three MIDI exercises: all 12 minor 6/9 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 46Minor-Major 7th Chords
How every m(maj7) chord is built by counting semitones (a minor triad (Lesson 9) with a major 7th on top, instead of the minor 7th a plain minor 7th chord uses), plus three MIDI exercises: all 12 minor-Major 7th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 47Minor-Major 9th Chords
How every m(maj9) chord is built by counting semitones (a minor-major 7th chord (Lesson 46) with a 9th stacked on top), plus three MIDI exercises: all 12 minor-Major 9th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 48Major 9th Chords
How every maj9 chord is built by counting semitones (a major 7th chord (Lesson 16) with a 9th stacked on top), plus three MIDI exercises: all 12 major 9th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 49Major 13th Chords
How every maj13 chord is built by counting semitones (a major 9th chord (Lesson 48) with a 13th stacked on top — the fullest stock major 7th-family chord), plus three MIDI exercises: all 12 major 13th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 50Major 7th♯5 Chords
How every maj7♯5 chord is built by counting semitones (an augmented triad (Lesson 10) with a major 7th on top, instead of the minor 7th an augmented 7th chord (Lesson 23) uses), plus three MIDI exercises: all 12 major 7th♯5 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 51Dominant 9sus4 Chords
How every 9sus4 chord is built by counting semitones (a dominant 7sus4 chord (Lesson 29) with a 9th stacked on top), plus three MIDI exercises: all 12 dominant 9sus4 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 52Dominant 13sus4 Chords
How every 13sus4 chord is built by counting semitones (a dominant 9sus4 chord (Lesson 51) with a 13th stacked on top), plus three MIDI exercises: all 12 dominant 13sus4 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 53Major 7sus2 Chords
How every maj7sus2 chord is built by counting semitones (a sus2 chord (Lesson 27) with a major 7th stacked on top), plus three MIDI exercises: all 12 major 7sus2 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 54Major 7sus4 Chords
How every maj7sus4 chord is built by counting semitones (a sus4 chord (Lesson 28) with a major 7th stacked on top, instead of the minor 7th a dominant 7sus4 chord (Lesson 29) uses), plus three MIDI exercises: all 12 major 7sus4 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 55Add11 Chords
How every add11 chord is built by counting semitones (a major triad (Lesson 8) with an 11th (4th) added, keeping the 3rd — distinct from a sus4 chord (Lesson 28), which removes the 3rd), plus three MIDI exercises: all 12 add11 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 56Diminished Major 7th Chords
How every °(maj7) chord is built by counting semitones (a diminished triad (Lesson 11) with a major 7th on top, instead of the diminished 7th a diminished 7th chord (Lesson 14) uses), plus three MIDI exercises: all 12 diminished Major 7th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 57Minor 7♭9 Chords
How every m7♭9 chord is built by counting semitones (a minor 7th chord (Lesson 15) with a ♭9th stacked on top, instead of the natural 9th a minor 9th chord (Lesson 42) uses), plus three MIDI exercises: all 12 minor 7♭9 chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 58Half-Diminished 11th Chords
How every m11♭5 chord is built by counting semitones (a half-diminished 7th chord (Lesson 17) with a 9th and 11th stacked on top), plus three MIDI exercises: all 12 half-Diminished 11th chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 59Power Chords
How every 5 chord is built by counting semitones (just a root and a perfect 5th, with no 3rd at all — the simplest possible chord shape), plus three MIDI exercises: all 12 power chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 60Split-Third Blues Chords
How every 7(♭3/♮3) chord is built by counting semitones (a dominant 7th chord (Lesson 13) with both the minor 3rd and major 3rd sounded together, instead of just the major 3rd), plus three MIDI exercises: all 12 split-third "blues" chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 61Quartal Chords
How every quartal chord is built by counting semitones (five notes stacked entirely in perfect 4ths, instead of the stacked 3rds every other chord in this app uses), plus three MIDI exercises: all 12 quartal chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 62Tone Cluster Chords
How every cluster chord is built by counting semitones (three adjacent notes struck together — a half step and a whole step stacked right on top of the root, with no 3rd, 5th, or 7th at all), plus three MIDI exercises: all 12 tone clusters around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 63Polychord (Slash Chord)
How every / chord is built by counting semitones (a major triad (Lesson 8) rooted a whole step above the bass note, stacked over a dominant 7th chord (Lesson 13) built on that bass note — the app’s reference voicing for "X/Y" slash-chord notation), plus three MIDI exercises: all 12 polychords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 64Neapolitan (♭II) Chords
How every ♭II chord is built by counting semitones (a plain major triad (Lesson 8), but rooted a minor 2nd (half step) above the tonic instead of on it), plus three MIDI exercises: all 12 Neapolitan chords around the circle of fourths, and 5 jazz plus 5 gospel chord progressions built around this color, in every key
Start lesson → Lesson 31Now Behold the Lamb — Song Trainer
Kirk Franklin's gospel classic "Now Behold the Lamb," played from its real piano accompaniment (right-hand chord comping + left-hand bass, both taken from the original arrangement) in every key — the song lesson whose harmony introduced the sus2, sus4, dominant 7sus4, and 6/9 chords taught in Lessons 27-30.
Start lesson → Lesson 65Every Praise — Song Trainer
Hezekiah Walker's gospel anthem "Every Praise," with all three parts — Alto lead vocal, piano right hand, and piano left hand — visible and playing together on their own full keyboards the moment the lesson opens, in every key.
Start lesson →Play along with real MIDI
Every lesson works instantly with a built-in synthesizer, and upgrades automatically to real MIDI hardware — output or input — in Chromium-based browsers via the Web MIDI API.
Works on any device
Built with plain HTML, CSS, and JavaScript — no build step, no framework — and laid out to work well on phones, tablets, and desktops alike.
Open and free to use
Released under the MIT License by HepziBen Technologies Limited — see the LICENSE file for details.