In first species counterpoint, each note of the counterpoint voice aligns with each note of the cantus firmus. This is the most transparent form and the one that most clearly shows the rules of consonance, voice independence, and part-writing.
The Rules of First Species
First species counterpoint is the starting point of all contrapuntal training. Its simplicity makes the fundamental rules maximally transparent: with one note against one note, every harmonic interval is exposed and must be justified. There is nowhere to hide a bad interval, no passing motion to excuse a dissonance, no rhythmic offset to reduce the impact of a poor choice. Each vertical relationship between the two voices stands fully revealed, and each must be defensible on its own terms.
The rules of first species counterpoint, as codified by Fux and refined by Jeppesen, can be stated as a compact list of constraints:
- Use only consonant intervals. Perfect consonances (unison, fifth, octave) and imperfect consonances (thirds and sixths) are permitted. No dissonances (seconds, fourths, sevenths, tritones) appear anywhere in the exercise.
- Avoid parallel perfect consonances. Two voices moving in the same direction by the same interval (parallel fifths: C-G then D-A; parallel octaves: C-C then D-D) are prohibited because they reduce the independence of the voices. Two voices that move in parallel perfect consonances sound like one thick voice, not two independent voices.
- Avoid similar motion to a perfect consonance. If two voices both move in the same direction (even by different intervals) to land on a perfect consonance, this is called "similar" or "hidden" motion and is prohibited in the outer voices, since it approximates the sound of parallel motion.
- Prefer contrary motion. When one voice moves up, the other moves down. Contrary motion is the gold standard of voice independence. Oblique motion (one voice holds while the other moves) is acceptable. Parallel motion by imperfect consonances (parallel thirds, parallel sixths) is acceptable and common.
- Avoid unisons except at the beginning and end of the exercise — the two voices touching at a unison momentarily merge.
- Begin and end on a perfect consonance. The opening interval should be a unison, fifth, or octave (with the cantus firmus typically in the lower voice). The final interval is always a unison or octave, signalling repose.
Consonance and Dissonance in Species Counterpoint
The classification of intervals as consonant or dissonant in species counterpoint follows the harmonic series logic discussed in ear training: perfect consonances (unison, fifth, octave) are most stable; imperfect consonances (thirds, sixths) are stable but coloured; seconds, sevenths, and tritones are dissonant. Notably, the fourth is treated as dissonant in two-voice counterpoint when it appears between the bass and an upper voice — this is a departure from the acoustic definition (perfect fourth is acoustically consonant) but reflects a functional reality: a fourth above the bass creates an unstable vertical sonority that demands resolution in tonal counterpoint.
This functional dissonance of the fourth above the bass is one of the most consequential rules in the entire tradition. It is the reason the second-inversion triad (the 6/4 chord) is treated as a dissonance in tonal harmony; it is the reason the cadential 6/4 demands resolution to a 5/3 sonority; and it is the reason fugal expositions must be careful about which voice carries the fifth of the harmony when entering. In three-voice writing, the fourth between upper voices is consonant again — only the bass relationship is critical.
Melodic Guidelines
Beyond the vertical (harmonic) rules, first species counterpoint imposes melodic guidelines for the written voice. The counterpoint line itself must be singable and musically satisfying, not merely a sequence of correct intervals against the cantus firmus:
- The line should have a clear overall shape — generally arch-shaped, rising to a single high point (climax) and then descending toward the cadence.
- Leaps should be followed by stepwise motion in the opposite direction. After a leap of a fifth or larger, the voice should "recover" by stepping back in the opposite direction.
- No more than two leaps in the same direction in succession; if two leaps occur in the same direction, they should outline a consonant triad.
- Avoid large awkward leaps: sevenths and augmented intervals (augmented fourth, augmented second) are entirely forbidden.
- End with a leading-tone step to the tonic (Ti-Do, in the upper voice) or a downward step (Re-Do in the lower voice for the standard authentic cadence; Phrygian cadence uses a half-step approach in the lower voice).
- Avoid repetition: the same note should rarely sound twice in succession in the counterpoint voice, and the same pitch class should not dominate the melodic shape.
Practical Exercise
Begin with a given cantus firmus of eight notes in C major: C-D-F-E-G-F-D-C (like a Fux cantus, it ends by step, 2-1). Write a counterpoint above it using only consonant intervals, applying the rules above. Choose each interval by asking: what consonant interval above this cantus firmus note makes a good melodic line and avoids the voice-leading problems outlined? Verify that no parallel perfect consonances occur between consecutive notes. Check that the line moves smoothly and has a clear melodic shape. Sing both voices simultaneously (or play on a keyboard) to hear whether the result sounds like two independent voices in dialogue.
A useful diagnostic when checking your work: cover the cantus firmus and look at your counterpoint line alone. Does it sing? Does it have a clear high point? Does it move predominantly by step with occasional leaps in service of shape? If the counterpoint line, taken in isolation, is not melodically satisfying, the exercise has failed even if every interval is technically consonant. The goal of species training is not interval-checking but melodic composition.
Common Errors and How to Diagnose Them
Beginners typically produce a recognisable set of mistakes. Direct fifths and octaves are usually caught by checking every pair of consecutive intervals — if both involve perfect consonances and both voices move in the same direction, there is a problem. Melodic tritones (the diminished fifth or augmented fourth outlined over two or three notes, even if intervening notes break the line) can be hidden but are audibly awkward. Repeated climax notes — the same high note returning multiple times — flatten the melodic arch. Cadences that lack a leading tone (or that use the wrong scale degree at the close) produce an unsettled ending that does not feel like an ending.
Sources and Further Reading
- Fux/Mann. The Study of Counterpoint. Norton, 1965. Part II, Chapters 1-2.
- Jeppesen. Counterpoint. Prentice-Hall. Chapter 3.
- Open Music Theory — Species Counterpoint (openmusictheory.net, CC BY-SA 4.0).
- Gauldin, Robert. A Practical Approach to Eighteenth-Century Counterpoint. Waveland Press. Chapter 2.
- Kennan, Kent. Counterpoint: Based on Eighteenth-Century Practice. Prentice-Hall.