A reference for guitar players learning music theory through the instrument.

• Keys
  All 12 major and minor keys on the keyboard, built from the whole/half-step patterns, with the scale playable.
• Chords
  The seven diatonic chords of every major and minor key, laid out by scale degree.
• Chord voicings
  Every way to play a given chord on the neck, generated rather than curated, with a rough difficulty score on each.
• Scales
  Pentatonics, blues, the seven church modes, harmonic and melodic minor — every note across the whole neck, in every key.
• Notes on the neck
  Every note on the fretboard, labeled.
• Ear training
  Drill one level at a time — 15 questions, no timer. Intervals from P4/P5/P8 up to all 12 played harmonically, plus a chord-quality ladder (major, minor, dom7, sus, dim…) heard as a block or an arpeggio.
• Ear test
  Take the full test: every level back-to-back, 5 questions each. Get a per-level breakdown and a shareable result at the end.