What are Hidden Fifths?

Hidden fifths (also called direct fifths) occur when two voices move in the same direction and arrive at a perfect fifth, even though the previous interval between the voices was not a fifth. This usually happens when one or both voices move by leap into the new interval.

Hidden fifths are most noticeable when they occur between the outer voices, such as the soprano and bass. In traditional classical harmony, they are often avoided—especially if the soprano leaps—because the motion can weaken the independence of the voices and create a sound similar to parallel fifths.

In classical counterpoint and voice-leading practice, composers carefully control hidden fifths to maintain clear separation between melodic lines. However, in many modern musical styles they are used more freely, since strict contrapuntal rules are less strictly enforced outside traditional tonal writing.