The Playing Changes series presents and expands on concepts from my book, The Living Jazz Tradition: A Creative Guide to Improvisation and Harmony published by CMA Press.
Jazz standards from the New Orleans, swing, and bebop eras are based on a system of chords and scales known as tonal harmony. This system originated in European classical music from the common practice period—roughly 1600 to 1900. Tonal harmony serves as a foundation for many styles of music, including pop, rock, folk, blues, country, and gospel.
A collection of notes is diatonic if it belongs to a single scale. For example, any melody or chord constructed with white keys on the piano is diatonic to the key of C major. Notes outside of the key signature, which in this case are the black keys, are called chromatic or non-diatonic tones.
Three-note chords called triads are among the building blocks of tonal harmony. Below are the seven
diatonic triads built from the notes of the C major scale. Each scale tone becomes the root of a chord:
Chords can be represented by Roman numerals or by jazz/pop chord symbols. Roman numerals show how progressions of chords relate to a key, and this makes them invaluable when transposing. The uppercase numerals represent major triads, and the lowercase numerals represent minor triads.
Jazz chord symbols identify each chord individually. They describe chord structures regardless of context or key of the song. Jazz charts and fake books use this system.
Next, look at diatonic triads in G major. The Roman numerals and chord types are identical, but the chord symbols change to identify the root of each chord:
Johann Pachelbel’s Canon in D is composed of diatonic triads (this excerpt has been transposed to C major):
The tonic is the first degree of a scale. It has a gravitational pull that draws other pitches toward it. When a melody lands on the tonic, it feels like “home” compared to other pitches. The tonic pitch serves as the foundation for a tonic chord, known as the I chord. When using Roman numerals, the key of the tonic is written before the harmonic analysis.
Dominant means V. The dominant pitch is a perfect fifth above the tonic and is the root of a dominant chord. In the key of C major, a G major chord is the dominant triad because it is built from the dominant note G. The dominant chord creates an instability that requires the tonic for resolution.
The word cadence originates from the Latin word cado, which means “to fall.” Musical cadences evoke feelings of tension and release, rising and falling.
Cadences lie at the center of most jazz harmony through the bebop era. The most common cadence is the resolution of dominant to tonic (V to I). This is called an authentic cadence and it is the backbone of tonal music.
“Happy Birthday to You” opens with a I–V–I progression:
Play the example above and pause before the last chord. Notice how the V chord wants to continue to the I chord. This illustrates chord function—the feeling and tendencies of each chord in relation to the tonic.
When a diatonic seventh is added to the dominant triad, this forms a dominant seventh chord:
Adding a seventh to a dominant chord creates the dissonant interval of a tritone between the third and seventh, in this case B and F. This tritone wants to resolve to C and E in the I chord:
Next in the series is “Playing Changes Part 3: Inversions and Voice Leading.”
Index of Playing Changes Articles
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