Diminished scales

Which one goes where

Half-whole — semitone, tone, semitone, tone — goes over dominant chords, especially a 7♭9. It supplies the ♭9, ♯9, ♯11 and 13 while keeping the natural fifth, which is exactly the set of tensions a 7♭9 wants. Whole-half — tone, semitone — goes over a diminished seventh chord, whose four notes it contains.

Getting them the wrong way round is the most common mistake with these two, and the tool will not let it happen: a half-whole scale does not contain the ♭♭7 that a diminished seventh chord depends on, so it is never offered for one.

Scale	Notes	Formula	Against the chord	Usage
A Half-whole diminished	A Bb C C# D# E F# G	1 b9 #9 3 #11 5 13 b7	1 b9 #9 3 #11 5 13 b7	Best choice
A Altered scale	A Bb C C# Eb F G	1 b9 #9 3 #11 b13 b7	1 b9 #9 3 #11 b13 b7	Common
A Phrygian dominant	A Bb C# D E F G	1 b2 3 4 5 b6 b7	1 b9 3 11 5 b13 b7	Common
A Major pentatonic	A B C# E F#	1 2 3 5 6	1 9 3 5 13	Colour

The books behind this tool

Knowing which scale fits the chord is where the question starts, not where it ends. Tension and Resolution is about what the line does once the scale is decided: where it aims, and why it lands.

Start here Project 02 · Jazz guitar

What the symmetry buys

Both scales repeat every minor third, which means there are only three distinct diminished scales in all twelve keys. One shape, moved up three frets, is a different scale name and the same notes. For a guitarist this is the cheapest material on the instrument: learn one box and you have covered four roots.

Scale	Notes	Formula	Against the chord	Usage
E Whole-half diminished	E F# G A Bb C C# D#	1 2 b3 4 b5 b6 6 7	1 9 b3 11 b5 b13 bb7 7	Best choice

Try it on your own chords

Open the scale finder →

Diminished scales

Which one goes where

The books behind this tool

Tension and Resolution

Jazz Guitar Comping

Jazz Harmony

What the symmetry buys

Try it on your own chords

The altered scale

Melodic minor in jazz

Secondary dominants