Non-diatonic Chords – I’ve Got Your Number

January 4, 2015

Alex Anest

Looking at jazz standards, the chord progressions can be daunting. But most of the chords fall into one of four categories – diatonic 7th chords, secondary dominants and their tritone substitutions, borrowed chords, and diminished passing chords.

Diatonic 7th chords are chords that are found in the key that the song is in. I, ii, iii, IV, V and vi. You can usually improvise in the key of I over these chords. Of course it helps to know the arpeggios and to be able to find the chord tones.

Non-diatonic chords are everything else. If a chord has at least one note in it that is not in the key of I, it is a non-diatonic chord. Secondary dominants are the most common.

Secondary dominants are chords that are V in relation to something other than I. V/ii, V/IV, V/V and V/vi are the most common. In C…

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