Chris Dobrian's patented foolproof 4-part voice leading rules for root-position triad progressions


For root-position triad progressions:

Rule 0) Whenever possible, double the root of the chord and have the 3rd and 5th each appear once.

Rule 1) When the root moves by fourth (such as I-IV or ii-V or V-I), there will be one pitch that's common to both chords. The bass moves from root to root. The common tone stays where it is. The remaining two voices move as little as possible, usually by step or third, in such a way as to result in a chord that conforms with Rule 0.

Rule 2) If the melody in the soprano is such that it makes Rule 1 impossible, try to move all the upper three voices contrary to the bass.

Rule 3) When the root moves by a second (such as I-ii or IV-V), there will be no common tones. The bass moves from root to root. The other three voices should move contrary to the bass.

Rule 4) When the root moves by a third (such as I-vi), there will be two pitches that are common to both chords. The bass moves from root to root. The common tones stay where they are. The remaining voice moves as little as possible, usually by step, in such a way as to result in a chord that conforms with Rule 0.