←Index
Axis System for Analysis
Tonic
C G D A E B F♯ D♭ A♭ E♭ B♭ F
Subdominant
C G D A E B F♯ D♭ A♭ E♭ B♭ F
Dominant
C G D A E B F♯ D♭ A♭ E♭ B♭ F

  1. The twelve pitch classes are divided into three groups, or axes: Tonic, Dominant, and Subdominant.
  2. Each Axis includes a pair of perpendicular branches on the circle of fifths.
  3. The primary branch contains the principal tone (Tonic, Subdominant or Dominant), and its relative tritone.
  4. The secondary branch contains minor thirds above and below the principal tone.
  5. Any chord may be substituted with any other chord whose root is on the same Axis, and retain the original function.
  6. Natural progression appears counter-clockwise on the circle of fifths (descending fifths), while regression appears clockwise (ascending fifths).
  7. Natural progressions among the axes include Subdominant to Dominant, Dominant to Tonic, and Tonic to Subdominant.