Similar motion
Similar motion (also called direct motion) means: two voices go in the same direction at the same time, both upwards or both downwards. It is the umbrella term for parallel motion, in which the distance stays the same, and for similar motion in the narrow sense, in which it changes.
- Latin
- motus rectus
- Meaning
- both voices rise or fall
- Special case
- parallel motion (same interval)
- Counterpart
- contrary motion
In the same direction
Two voices can move from one sonority to the next in three ways: they go in opposite directions, one stays put, or both go in the same direction. The last possibility is called similar motion, Latin “motus rectus”. The name says nothing about whether the intervals stay the same; it describes only the direction.
Similar motion with a changing distance
Both voices rise. The lower goes C–D–E in steps, the upper E–G–C in leaps. The distance changes from the third via the fourth to the sixth: similar motion, but not parallel motion.
How it is classified
Some textbooks divide it once more. If the interval between the voices stays the same, one speaks of parallel motion. If it changes, it is similar motion in the narrow sense. The terms are not quite uniform in the literature, which is why a look at the table is worthwhile, setting all four cases side by side.
| Kind of motion | What the voices do | Example |
|---|---|---|
| Similar (direct) motion | both in the same direction | third → fourth → sixth |
| Parallel motion | similar motion with the same interval | third → third → third |
| Contrary motion | one rises, the other falls | octave → tenth |
| Oblique motion | one voice stays put | third → fifth |
What is delicate about similar motion
Similar motion is by no means forbidden in itself, it occurs in every texture. It becomes delicate only when both voices approach a perfect interval at once, that is, an octave or a fifth. Such a sequence is called hidden fifths or octaves, and strict harmony teaching avoids it because the voices lose their independence. Together with contrary motion and oblique motion, similar motion forms the three basic kinds of voice leading.
Common mistakes
- Equating similar motion with parallel motion: parallel is only the case with a constant interval.
- Understanding “similar” as “without leaps”: what is meant is the common direction, not the width of the steps.
- Regarding every similar motion as a mistake: only motion into perfect intervals is restricted in strict teaching.
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Related terms
Parallel motionContrary motionOblique motionParallel fifthsParallel thirdsCounterpointInterval
Editor: Maik Krohm · reviewed on 3 October 2026
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