We always depart from a Cantus Firmus (CF).
HARD RULES
- Use only natural notes and Bb
- In FIRST SPECIES we only use perfect and imperfect consonances. Remember that the perfect 4th is considered a dissonant (!).
- Skips of augmented and diminished intervals, and skips larger than a sixth are prohibited (except that octaves are allowed)
- Outlines of augmented fourth are forbidden and a diminished fifth must completely be filled in and followed by a step in the opposite direction
- Begin and end with perfect consonances between the two parts
