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  • Writer's pictureAdam Hope

Harmonising the Locrian mode

Updated: Jun 11, 2020

The Locrian mode can be tricky to use as it's the only mode that doesn't contain a perfect fifth from the key note of the mode. That is, it can give a very unsettled feeling, as the chord built on the first degree of the mode contains a diminished fifth if we try to build it as a three-note triad. So in this blog, I'll give a quick overview of the mode, and explore some bitesize techniques for harmonising the Locrian mode. It has a unique and distinctive character which, if used to good effect, can create an arresting and absorbing sound world.

The Basics of the Locrian mode

If you take the scale of C major, and arrange the notes from B to B, you get the Locrian mode:

I like exploring the modes relative to a single tonality because we then have a basic palette of tones, which we re-order and re-arrange (and for many, just starting out with modes, the diatonic white keys are the easiest to deal with).

Notice that the semitones fall between the same scale degrees as they do in C major. It's important to notice this because the sound world of the Locrian mode comes from the placement and emphasis of the semitones. Yes, we have the same notes as C major, but the improviser must learn to shift musical emphasis onto different notes – the B natural becomes the gravitational centre of the mode, with a characteristic semitone fall onto the note.


Just before we move to harmonisation proper, it’s worth exploring the clausulae (note against note melodic cadences) available in the Locrian mode. The benefit of using the clausulae is that you can give a strong sense of modal identity to the key note of the mode, and intensify the gravitational pull of this note.

These clausulae should form landmarks in a modal improvisation. That is, try to ensure that they feature at the conclusion of phrases, which will re-enforce the unique quality of the Locrian mode.

Harmonisation 1 – Highlighting the modality

I like to start, particularly with the modes, by finding harmonic patterns that constantly reference the key note. This puts the modal centre in the ear and creates a feeling of harmonic movement towards (in this case) the B natural.

Just a few of points about the harmonisation above:

  1. I've chosen to use three-voice harmony. I think this is a great way of working, especially with keyboard harmony and improvisation. Focusing on creating a smooth bass line to complement a melody, and having to add just the right chord tone to realise the harmony forces the mind to think carefully and quasi-contrapuntally. It's great for discipline;

  2. I try to introduce variety and interest in the harmony, so I've added some dissonance (7-6 on the F bass) and alternated first inversion with root position chords;

  3. I've applied the clausulae as mentioned above. This gives a strong sense of the character of the mode by establishing the cadential impetus on the B natural.

Harmonisation 2 – The Modal Scale in the Upper-voice

Now we can move to harmonising the complete scale in ascending and descending forms. Notice I haven't limited myself to using the same harmonies – I think it's important to highlight that there are lots of suitable combinations you could find that work well; context often demands how we harmonise. What I like about the following harmonisations is:

  1. They observe use of the clausulae when cadencing at the end of the scale;

  2. They have a smooth, mostly step-wise bass line, which also highlights the modality.

Here's one possible harmonisation for the ascending Locrian mode:

...and one for the descending version:

Notice, again, that there is a smooth bass progression featuring a single disjunct interval. Both bass lines feature a point of repose – a long note in the bass at about the halfway point. This provides a welcome moment of relief, thus making it more musical than if we simply played a rhythmically uniform progression of harmonies. It also allows for the introduction of some harmonic interest, with the 8-7 progression over the F bass.

It's important to make all of this feel like music-making and not just keyboard exercises. This solves the problem of segueing into improvisation. If we are already making music, we are simply expanding and developing. The treatment of these keyboard exercises in isolation means we still have to help the student to bridge the gap between theory and practice. Why not kill two birds with one stone?!

From here, once the patterns are in the fingers, ear, and mind, transpose to a couple of other tonalities – say 2 flats and 3 sharps, just for variety. It will be important to adapt your harmonisations to the changes of tone and texture that different registers demand. Then begin to experiment with phrases, and build these up into 8 and 16 bar sections. I'll say it again: Always aim to cadence! – it helps make sense of your improvisation. In the modal style (and particularly with a slightly strange-sounding mode like the Locrian), cadence and phrase is even more important for us, and for the listener.

I've always found the quality of the modes well-suited to improvisations in the liturgy. They are atmospheric, transportive, and absorbing. I hope this short blog gives you some bitesize ideas for your own work with the Locrian mode, and that you enjoy exploring the mode in your own context!

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