In music, voice leading is the continuity between pitches or notes played successively in time. For example, when moving from a root position C triad or chord played C-E-G to an F triad in second inversion, played C-F-A, you might say that the middle “voice” rises from E to F while the top “voice” rises from G to A, this being a way to “lead” those voices. Instead of thinking of the two successive chords vertically as separate, we are concentrating on the “horizontal” (temporal or linear) continuity between notes. Concern for voice-leading often means a predominance of stepwise motion and may assist or replace diatonic functionality.
The most famous set of rules for voice leading appear in the book on species counterpoint written at the beginning of the eighteenth century by Johann Josef Fux (Gradus ad Parnassum, 1725). Fux’s voice-leading rules aimed at creating a fluid and elegant contrapuntal style that represented an aesthetic ideal for many composers and writers. By the end of the nineteenth century, as tonal music continued to change, teachers and theorists found themselves in the slightly odd position of recommending a set of rules for counterpoint and then showing how composers in fact broke most of them in one way or another. It is worth bearing in mind that there are no rules that describe exactly how any musical style operates. The history of tonality is not a seamless progression.