Beginner's Guide To Diminished Chords | Part 2: Using Diminished Chords In Progressions

Yash
Jul 7, 2022
6 min read

Updated: Oct 8, 2022

In Part 1, we looked at how to make diminished chords. Now we are going to learn how to use them in chord progressions. But before learning the use of diminished chord, it is important to understand their sound, as well as what makes them useful.

Resolution Of Tritone

The core concept of a diminished chord is creation and resolution of tension. Diminished chords have a tense sound because of the presence of tritone in them (1-♭5), and this sound needs resolution. Usually, a tritone is resolved in one of two ways. Either both the notes move half step away from each other, or half step towards each other.

E.g.: B-F could either resolve to B♭-G♭ or C-E. Using this concept, we can conclude that a diminished chord containing B-F tritone could resolve to a chord containing B♭-G♭ (That could be

E♭ Minor or G♭ Major) or a chord containing C-E (That could be C Major or A Minor). Some of those resolutions will work better than the others, but they are all possibilities.

Therefore, depending on what kind of resolution we are using, we have some common ways of using the diminished chord.

1. Diatonic Diminished

As explained in Part 1, the first encounter that most people have with the diminished chords is the vii° chord in a major scale. Let's analyze its function in any one key and then generalize it for all major keys.

In C Major, the vii° chord is B°. The notes of B° are B-D-F. The tritone is B-F. This tritone could either resolve in C-E or B♭-G♭, but B♭ and G♭ are not diatonic to the C Major scale, therefore for now we will not use them.

So, we are now left with the other option of resolving B-F on C-E. The chords containing C and E in the scale of C Major are either C Major (C-E-G) or A Minor (A-C-E), so both of those are valid resolutions. However if you try to play them on the piano, you'll notice that going from B° to C feels so much more satisfying than going from B° to Am.

Converting all those chords to roman notations, we see that the diatonic diminished chord in a major scale (vii°) can either resolve to the "I" or the "vi". It is usually used with the I chord.

Remember that the vii° can also be used as a 7th chord. Diatonically, it would be viiø.

In conclusion, the first way of using diminished chord is in a "vii°-I" cadence towards the end of a chord progression to give a feeling of resolution. This can also be thought of as a substitute for the V7-I cadence, since both V7 and vii° chord have the same tritone. Eg: I-IV-vi-viiø-I instead of I-IV-vi-V7-I.

Keep in mind that since diminished chords are so unstable, you might wanna avoid holding on to them for too long. However this is a creative choice, as sometimes sustained tension is desired.

2. Passing Diminished

In the first method we saw how to use diminished chords diatonically, where it was resolving from vii° to I. Basically, the diminished chord has moved to a major chord half step above it. Eg.: B° to C Major, E° to F Major, etc.

So, we can extend the logic of this method to a non-diatonic context. Let's say we have a chord progression in the key of G Major. The progression is Am-D-C-G (ii-V-IV-I). We can think of one of these chords as a temporary I chord, and play the diminished chord that is half step below it. For example, we can play C♯° before playing D here. The full progression now becomes Am-C♯°-D-C-G. In this method, the resulting diminished chord is non-diatonic. Usually this chord is played for a brief duration before quickly resolving to the target chord.

Even though the logic dictates that a passing diminished should be resolved to a major chord half step above it, this also works pretty well with minor chords, despite the absence of the tritone resolution.

Passing Diminished is the diminished chord half-step below the target chord, played briefly to create quick tension and resolution. You can use either diminished triad, half diminished chord or full diminished chord in this situation.

Passing diminished chords are often used to create a chromatic bassline. For example, in the chord progression A-Bm-E-A (I-ii-V-I), we are moving from A to Bm, and the roots are a whole step away. We can play a passing diminished for the Bm, which would be B♭°. Then, the root would be going from A to B♭ to B, creating a very nice chromatic pattern. The new progression becomes

A-B♭°-Bm-E-A.

If you liked this concept, you might wanna head here to check out other similar ways of going out of the scale to create interesting progressions.

3. Auxiliary Diminished

Auxiliary diminished chord is the full diminished chord formed on the same root as the target chord. For example, the auxiliary diminished for G Major would be G°7. This chord is a bit different in its function, since it doesn't come from the resolution of tritone. It is simply used to prolong the harmony. For example, if you are continuously playing the same chord in multiple bars, you can insert a couple of these auxiliary diminished chords occasionally to create interest.

It can also be used right before landing on any chord in the same way as the passing diminished, but this doesn't always sound good, since there is no resolution going on.

4. 2-5-1 in minor key

Here are the diatonic chords of the minor scale:

i - ii° - ♭III - iv - v - ♭VI - ♭VII

In this scale, we don't have the diatonic diminished on the 7th scale degree. Instead, we have it on the 2nd degree. If you have studied any amount of jazz, you would know the wide use of 2-5-1 progressions in it.

So, in case of minor scale, the 2-5-1 progression becomes ii°-V-i. Since this is jazz, we would be using 7th chords, leading us to iiø - V7- im7.

This progression is very useful for modulation too, as we'll see in the next topic.

5. Modulating

Since diminished chords create tension, it is a no brainer to use them for modulation.

The most direct way is simply to use a passing diminished chord to resolve to the new target key. For example, if you want to go from C Major to A Major, you can play C - A♭ø - A. This method takes minimum effort, but works fine most of the time.

A bit more interesting method is to treat a diminished chord as the ii° chord of the target key. For example, take a look at this progression:

C - F - G - C - F - Fø - B♭ - E♭m

Here, the first four chords are just the I-IV-V-I progression in the key of C Major. Then, we have another IV chord, going to ivø. But looking at it from a different perspective, it is the iiø in the key of E♭ Minor. So from here, I just added the V chord in the key of E♭ Minor to create the famous iiø-V-i progression, leading up to E♭m, thus modulating to a new minor key.

You can use this even more creatively if you end it on E♭ instead of E♭m, because that comes as a surprise to listeners whose ears have become attuned to this progression ending on a minor chord.

There is yet another way of using diminished chords for modulation, and it uses full diminished chords. I'll be exploring those in another article, since it requires a lengthy explanation.

Conclusion

Diminished chords operate on the principle of resolution of tritone by moving half step outwards or half step inwards

Diatonically in a major scale, the half diminished chord is found on the 7th scale degree, and it is a substitute for the V7 chord, to be used as a vii°-I cadence at the end of a phrase

Passing diminished triads or half diminished chords are built on the note that is half step below the target major (or minor) chord. They are played briefly to make the movement to the target chord more interesting.

Auxiliary diminished chords are built on the same root as the target chord. They are used to prolong the harmony by providing some color to a chord being played repeatedly.

In minor key, the diatonic diminished chord is used in iiø-V7-im7 progressions.

Diminished chords can be used for modulation to a new key by treating it as the iiø chord of the target key.

In the next part we will be looking at extensions that we can use with diminished chords and how to improvise over them.

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