Jazz Piano: 3 Steps to Reharmonize Pop Songs

Chord extensions and alterations transform simple playing into advanced, colorful music. Extensions are scale notes added to triads (1-3-5), creating 1-3-5-7 (seventh), 1-3-5-7-9 (ninth), and 1-3-5-7-9-11 (eleventh). The sharp 11 (same as sharp 4) is preferred over the 11 for major chords to avoid clashing with the third. The 13 is the same note as the 6. Seventh chords are built by following the same scale for all chords in a progression, playing every other note. Voice leading creates smooth transitions by minimizing movement between chords, keeping common notes. Chord inversions rearrange notes so the root is not in the bass, enabling smoother transitions. After mastering seventh chords, musicians extend chords further by adding ninths, elevenths, and thirteenths. For major chords, use the ninth and thirteenth, avoiding the eleventh. The third and seventh are most important as they define chord quality. Alterations are applied by raising or lowering chord tones by a half step, creating tension. Passing chords are added between main chords, and extending and altering them creates dissonance that builds stronger transitions and creates dynamic musical moments.

Extended chords are built by stacking notes in thirds on top of a basic seventh chord, which forms the core identity. Extensions like 9th, 11th, and 13th are added separately and named as modifiers. Extensions can be altered using sharp or flat notation (e.g., flat 9, sharp 11). Writing conventions place alterations after the chord name, typically in parentheses or superscript. When an extension number is altered, you must 'back up' to the previous chord level (e.g., 'F dominant 7 flat 9' instead of 'F9 flat 9'). In jazz, the fifth is often altered using sharp 5 or flat 5 notation. The term 'altered chord' in classical theory refers to chords changed so they no longer belong to the normal chord set of a key, while in jazz it typically refers to chords with sharp 9, sharp 11, or other alterations.

Extensions are notes from the scale that remain after playing a triad (e.g., in D major, after playing D-F#-A, the remaining notes are D, F#, A, B, and C#), while alterations are notes from outside the scale that can be added to create tension and color (e.g., Bb, F, G#, A#, and D in D major). By strategically adding these notes to basic triads, musicians can transform simple chords into richer, more sophisticated harmonies without complex techniques, making advanced chord voicings accessible for worship and gospel music.

Musical intervals (second through octave) form chord foundations. Extensions (ninth, eleventh, thirteenth) occur when notes double an octave higher. The seventh acts as a bridge to extensions and must always be present. Only the ninth can be both flattened and sharpened. The eleventh can only be sharpened (no flat eleventh exists). The thirteenth can only be flattened (no sharp thirteenth exists). Extensions are named by distance from root: ninth = second, eleventh = fourth, thirteenth = sixth. Understanding these principles enables effective chord construction.

Altered extensions modify standard extensions: flat 9, sharp 9, sharp 11, and flat 13. These are almost always found on dominant chords. The altered notes sit atop normal dominant chords. Parentheses are used to avoid ambiguity between chord roots and qualities. Examples include seven flat 9 (dominant + minor 9), seven sharp 9 (dominant + augmented 9), sharp 11 (dominant + augmented 11), and flat 13 (dominant + flat 13).

Tritone substitution replaces a dominant seven chord with another dominant seven chord a tritone away. This works because both chords share the same third and seventh notes (inverted), preserving the chord's fundamental character while introducing chromatic tension. The technique applies to any dominant chord resolving to a tonic. In the 2-5-1 progression, substituting G7 with D♭7 creates a chromatic walk-down effect. Secondary dominance expands possibilities by adding V chords before each chord, generating multiple substitution opportunities. In circle-of-fifths progressions like 3-6-2-5-1, converting chords to secondary dominants enables sophisticated chromatic voice leading through strategic tritone substitutions.

Three main techniques for juicy transition chords: (1) Secondary dominants create tension by placing dominant chords before diatonic chords (e.g., D7 as V of G minor 7); (2) Tritone substitution approaches targets from a half step above using dominant chords (e.g., Ab7 instead of D7); (3) Moo chord is a major triad with added 2nd over the 3rd, creating modern sound (e.g., D/F# for target C minor 7). Each technique adds tension, voice leading, and harmonic interest. These can be combined in progressions like 1-6-2-5 to create sophisticated harmonic movement.

Secondary dominant substitution replaces a diatonic minor seven chord with a dominant seventh chord that functions as a leading tone to that chord, creating stronger harmonic weight through tonicization. Tritone substitution replaces a dominant chord with another dominant chord a tritone away, always a half step above the target chord. Both techniques exploit harmonic relationships to create tension and resolution. The one-three-five-seven voicing structure underlies all examples, with hinge notes adding extension and color. These substitutions demonstrate how musicians can transform predictable progressions into expressive vehicles by understanding functional harmony and voice-leading principles.

A secondary dominant passing chord is used when going from the one chord to the five chord. The secondary dominant is a dominant seventh chord that resolves to the two chord. In the key of G, an A7 chord is used as a secondary dominant because it's not diatonic to the key. Tritone substitution involves using a dominant seventh chord separated by an augmented fourth distance (a tritone). In the key of G, an Eb7 or D#7 can substitute for the A7 chord because the distance from A to D# is an augmented fourth.

Tritone substitutions are a jazz harmony technique where a secondary dominant chord is replaced by another chord a tritone (three whole steps) away, creating a similar harmonic function while adding tension and color; this technique is commonly used in jazz improvisation and composition to create more sophisticated harmonic progressions.

Jazz improvisation can be understood through five progressive levels: Level 1 (playing by ear with intuition), Level 2 (using scales and keys), Level 3 (chord theory and arpeggios), Level 4 (substitutions and alterations), and Level 5 (tension and release mastery); each level builds upon the previous one, with no objectively right or wrong note choices—only more or less appropriate sounds based on context and personal style.

Jazz improvisation operates on a structured framework where each musician contributes to collective creativity: the rhythm section (bass, drums, piano) establishes the harmonic foundation and groove, while the horn section creates melodies and solos; musicians use specific scales (like mixolydian for dominant 7th chords and dorian for minor 7th chords) that correspond to each chord in the progression, enabling spontaneous composition while maintaining harmonic coherence within common forms like the 12-bar blues.

Jazz improvisation requires riding the edge where musicians either succeed or fail completely. This edge is where the spark of inspiration exists, enabling musicians to achieve things they never thought possible. Fast playing demands both mental speed and technical ability, and when successful, it happens spontaneously because musicians create it in the moment rather than practicing it beforehand. Musicians must develop their ears through repeated practice to recognize harmony, discord, and musical direction, allowing them to make adjustments without conscious thought. A critical skill is listening to what is happening around you, which enables musicians to simply play music naturally.

Effective jazz improvisation practice requires starting simple by focusing on a single key (such as C major) and working through the 251 chord progression (ii-V-I). The 251 consists of D minor 7, G dominant 7, and C major 7 in C major. Keeping practice within one key helps track experimented ideas. The 2516 variation loops back on itself (adding A dominant 7), creating a repeating cycle ideal for experimentation. Chord tone soloing forms the core technique, using only the root, third, fifth, and seventh of each chord. Approximately 80% of jazz improvisation focuses on chord tones, with the ninth optionally added as extended harmony. This systematic approach builds foundational skills before introducing complexity.

Jazz improvisation involves creating spontaneous musical variations over chord progressions by understanding harmonic structures, using scales and arpeggios, and developing musical vocabulary through practice on standards like 'Darn That Dream,' 'If I Were a Bell,' and 'Stella by Starlight.'