In music theory
, contrary motion
is the general movement of two melodic lines
in opposite directions. That is, when one of the lines moves up, the other line moves down. If the voices always move by the same intervals (in opposite directions) they are said to be in strict contrary motion
The following example shows two voices in contrary motion:
Contrary motion is contrasted with:
- similar motion (movement of two melodic lines in the same direction, but with the interval between them changing);
- parallel motion (movement of two melodic lines in the same direction, keeping the same interval between them) [this is also called direct motion]
- oblique motion (movement of one melodic line while the other remains at the same pitch).
Contrary motion is important to maintain independence of melodic movement in contrapuntal writing.