Guidelines for writing a 2-part invention Theory Things   William Wieland
  • Refer to Owen's Modal and Tonal Counterpoint chapter 18 for guidelines about structure.
  • Write 2 parts, but imply triads and seventh chords.
  • Write NO Perfect Parallels or parallel dissonances.
  • In authentic and deceptive cadences, resolve scale degree 7 to 8 and scale degree 4 to 3.
  • Resolve chord 7ths down by step.
  • Do NOT double active tones, i.e. the leading tone, altered tones or 7ths of 7th chords.
  • Do not overlap voices.
  • Avoid augmented or diminished melodic intervals unless a 7th chord or diminished triad is outlined.
  • Follow large melodic leaps by step in the opposite direction.
  • Do not approach a chordal seventh by a descending leap.
  • Do not approach perfect harmonic intervals by parallel or similar motion. Two exceptions:
    • Perfect Fourths
    • Horn Fifths
  • Do not write succesive perfect octaves or unisons in contrary motion.
  • Do not write succesive perfect fifths in contrary motion.
  • Resolve tritones properly. (The A4 resolves to a 6th and the d5 resolves to a 3rd.)
  • Resolve altered pitches by ½ step in the direction of their alteration.