Basics of Classical Harmonic Syntax

Three Main Harmonic Tendencies

Common-practice composers tend to write chord progressions in a certain direction. They prefer root movement by descending 5th, descending 3rd, and ascending 2nd. They often mix these in a single phrase.

The three other possibilities do exist in this music (ascending 5th, ascending 3rd, and descending 2nd), but are rare or occur as parts of sequences.

The following lists are arranged to start with the most common version of each root movement first, but they are not exhaustive. If you looked hard enough, you could probably find any two chord possibility, but few of them would be as common as V–I, ii–V, IV–V, and I–V.

Root Movement by Descending 5th

  • V–I
  • ii–V
  • I–IV
  • vi–ii

Root Movement by Descending 3rd

  • IV–ii
  • I–vi
  • vi–IV
  • vii°–V

Root Movement by Ascending 2nd

  • IV–V
  • V–vi
  • vii°–I
  • I–ii

Other Root Movements

by Ascending 5th

  • I–V
  • IV–I

by Descending 2nd

  • I–vii°
  • vi–V

Here is a chart combining all of the common root movements listed above.

First Chord Next Chord Possibilities
I
 ii, IV, V, vi, vii°
ii
 V
iii
 –
IV
 I, ii, V
V
 I, vi
vi
 ii, IV, V
vii°
 I, V

Things to Notice

  • I goes to every chord.
  • Every chord can go to V.
  • ii only goes to V.
  • iii is so uncommon in major to not even show up.
  • V only goes to I or deceptively to vi.
  • vi and IV are the next most versatile chords after I.

Additions in Minor (III and VII)

III is more common in minor and usually goes to vi or IV. It is preceded by i or VII, the subtonic major triad. VII–III sounds like V–I in the relative major, but the music usually immediately turns back to minor.

Should Your Own Music Follow These Guidelines?

Short answer: Only if you want it to.

Long answer: These are strict guidelines, but they are a generalization of how Mozart and Bach might have chosen harmonies. Other tonal composers are happily willing to step outside these prescriptions when it suits them, which is pretty often.

The history of music that has (what we call) chords is centuries long. Most other styles that use chords are much more free and willing to go anywhere with any chord. So follow your intuition and built up some musical craft. Write lots of music; use chords; don’t use chords; use Mozart as a guide; use Chuck Berry as a guide; make up your own guide; don’t use a guide; it’s really up to you.

A recommendation: don’t let music theory based on dead people’s music get in the way of your own creativity. If it helps, great; if it doesn’t, throw it away after your done with school. Pick it up again a few years down the road, and see if it is useful then. They’re just ideas based on old music.