In music theory, a leading note is a term used to describe the seventh note of a diatonic scale that is one half-step below the tonic or root note. It’s also known as the “leading tone” because of its tendency to lead or resolve to the tonic note, creating a sense of harmonic tension and resolution.

What is a Diatonic Scale?
Before we dive deeper into understanding what a leading note is, let’s first understand what a diatonic scale is. A diatonic scale is a seven-note musical scale that consists of five whole steps and two half-steps in each octave. The most common example of a diatonic scale is the major scale, which includes the notes: Do-Re-Mi-Fa-Sol-La-Ti-Do.

How to Identify a Leading Note?
To identify the leading note in any given key, you can simply look at the seventh note of that key’s diatonic scale. For example, in the key of C major, the seventh note would be B natural, which is one half-step below C. In the key of F major, it would be E natural, and so on.

The Importance of Leading Notes
Leading notes play an essential role in creating harmonic tension and resolution within music. When a melody or chord progression includes a leading note, it creates an expectation for resolution to follow. This creates tension within the music that makes it more engaging and intriguing for listeners.

Leading Notes and Chord Progressions
In chord progressions, leading notes often appear as part of dominant chords. Dominant chords are built on the fifth degree of any given key’s diatonic scale and include both the leading tone as well as other notes that create harmonic tension.

For example, in C major, G would be considered the dominant chord since it’s built on the fifth degree of the C major scale. The G dominant chord includes the notes G-B-D, with B being the leading note. The B creates a sense of tension that resolves when it moves up to C, which is the root note of the key.

The Role of Leading Notes in Melody
In melodic composition, leading notes are often used to create a sense of resolution and closure. For example, a melody might start on the tonic note and include a series of notes that eventually lead up to the leading tone. This creates tension and anticipation for resolution to follow.

When the melody finally resolves by moving up to the tonic note, it creates a satisfying feeling for listeners. This is why leading notes are so important in creating memorable and impactful melodies.

Conclusion
In conclusion, a leading note is an essential element in music theory that creates harmonic tension and resolution within music. It’s identified as the seventh note of any given diatonic scale that is one half-step below the tonic or root note. By including leading notes in both chord progressions and melody composition, musicians can create engaging and memorable pieces that leave a lasting impression on their listeners.