An instructional system for teaching music theory incorporates a human-readable harmony matrix which displays at least one repeat pattern of indicia corresponding to a particular placement of the notes of the twelve note scale. This pattern is arranged so that major or minor chords may be formed by rotations and/or inversions of a basic set of patterns. These patterns depict the interrelationship of the various chords. Transposition of chords from one key to another may be readily accomplished by moving the pattern across the matrix. The matrix pattern may also be used to depict and build chord progressions. The system operates to provide a two-dimensional representation of the relationship between musical tones and may be implemented in a variety of systems for teaching music theory.