Melodic Rules

These rules governing the melodic flow of each counterpoint are common to every species. I'll add to the list, or clarify the wording, as I come to understand them better.

1. Forbidden skips: augmented fourth, major sixth (up or down), minor sixth (down only), seventh, any interval greater than an octave.

2. "Exposed" tritones are forbidden. That is, no run of notes in a single direction should be an augmented 4th from end to end.

[NOTE: Since all of these exercises are written in their natural modes, the special notes to watch out for are F and B-- an augmented fourth when taken together. There can be no jumps between F and B, and no runs that begin on one can end on the other. Beware of F and B!]

3. Leaps of an ascending minor sixth or octave, or a descending octave must be "recovered." That is, such a large skip must be followed immediately by a step back into the range covered by the leap. (Fux often "recovers" using a skip of a third back into the big leap.)

4. Do not repeat notes. (Though Fux makes many exceptions in Species One, repeated notes are rare in the other species.)

5. Avoid multiple skips in the same direction. (This is a guideline-- Fux contradicts this advice all the time. See, e.g., page 46, in the 2nd species phrygian example, he skips 4th, 5th, and 4th in the same direction: c-f-c'-f'.)

Definitions, and the only rule of counterpoint...

This is the only background information Fux expects.

Intervals

Perfect consonances: Unison, fifth, and octave.

Imperfect consonances: Six and third.

Dissonances: Second, fourth, diminished fifth, tritone, and seventh.

I have a question: What's a tritone, if neither a fourth nor a diminished fifth?

Motion

"Direct motion results when two or more parts ascend or descend in the same direction by step or skip."

"Contrary motion results when one part ascends by step or skip and the other descends-- or vice versa."

"Oblique motion results when one part moves by step or skip while the other remains stationary."

The four rules of counterpoint

1. From one perfect consonance to another perfect consonance one must proceed in contrary or oblique motion.
2. From a perfect consonance to an imperfect consonance one may proceed in any of the three motions.
3. From an imperfect consonance to a perfect consonance one must proceed in contrary or oblique motion.
4. From one imperfect consonance to another imperfect consonance one may proceed in any of the three motions.

It seems to me the four rules are a roundabout way of saying one thing: never use direct motion to enter a perfect consonance.

It is necessary for you to know that in earlier times, instead of our modern notes, dots or points were used. Thus one used to call a composition in which point was set against or counter to point, counterpoint; this usage is still followed today, even though the form of the notes has been changed. By the term counterpoint therefore is understood a composition which is written strictly according to technical rules.