“So What” opens Miles Davis’s 1959 album Kind of Blue, the best-selling jazz album of all time. It’s the defining example of modal jazz: instead of fast-moving chord changes, the tune sits on one scale for long stretches, giving soloists room to build melodies from scratch. Bill Evans, John Coltrane and Cannonball Adderley all play on the original.
The form is a 32-bar AABA. The A sections are 16 bars of D Dorian (Dm7), the bridge moves up a half step to eight bars of Eb Dorian (Ebm7), and the last A returns to D Dorian. The head is a call-and-response between the bass, which plays the melody, and the piano and horns, which answer with two chords. Those answering chords are the famous “So What voicings”: three stacked fourths with a major third on top.
Improvising on “So What” is about creating interest without chord changes to push you. Use D Dorian, but don’t just run the scale. Build motifs, short melodic ideas, and develop them through repetition and variation. Try playing in fourths, using pentatonic scales built on different notes of the mode (D minor pentatonic, E minor pentatonic, A minor pentatonic) and stepping briefly “outside” before resolving. When the bridge moves to Eb Dorian, make the shift audible by emphasizing Gb and Db.
Practice with a drone or a simple vamp. Spend a few minutes improvising using only three notes, then four, then the full mode. Learn the So What voicings and move them up and down the D Dorian scale; pianists and guitarists use these everywhere in modern jazz.
Common mistake: losing track of the 16-bar A sections. Count carefully or listen for the drummer’s cues when the bridge arrives.
Recordings to study: the Kind of Blue original, Miles’s faster live versions from the 1960s, and John Coltrane’s “Impressions,” which uses the same form. Learn more about the composer on Miles Davis’s Wikipedia page, and find more modal jazz lead sheets on Minedit.