This was another unplanned improvisation. I sat at the piano not knowing what would emerge. The title was something I came up with in hindsight, as always.
The title Triptych in B♭ reflects the piece on several levels. On the surface, it describes the rhythmic fabric of the music — built around rapid triplet motion in both hands, where left-hand arpeggios and right-hand broken chords interlock in perpetual dialogue. But the word triptych also describes the form: three sections unfolding as contrasting yet connected panels. The opening and closing sections, both grounded in B♭ Mixolydian ♭6, frame a more reflective central panel in B♭ Dorian. Together they form a kind of ternary structure — motion, reflection, return — where harmonic colour shifts like light passing through stained glass.
As well as its rhythmic and structural connotations, I was also inspired by the older visual idea of a triptych. In medieval art, a triptych’s three panels often reveal different aspects of a single vision: two outer wings that open onto a luminous centre. That image feels fitting for this improvisation. The outer sections burn with kinetic energy, propelled by their triplet pulse and vivid, magical Mixolydian ♭6 colour, while the middle section opens inward — slower, more spacious, and quietly illuminated. The whole piece, then, becomes both musical and metaphorical: three phases of being in dialogue, three expressions of one tonal centre, united under the key of B♭.
Musical Details
This improvisation felt like a tightrope walk between precision and abandon. The texture that anchors its opening — rapid, interlocking triplet patterns between the hands — created both forward motion and peril. My left hand traces one-octave arpeggios in continuous motion while the right hand simultaneously plays a broken-chord figure in a different pattern: top, bottom, middle, repeating, but with different top notes. The top voice traces the melody, gently colouring and extending each harmonic change.
Harmonically, the first section is in B♭ Mixolydian ♭6, cycling through a progression that touches G♭ major, B♭ harmonic minor, and returns home again — a restless loop that circles brightness and shadow.
After this, the music releases into B♭ Dorian, where the pulse loosens and the texture opens with extended, wide left-hand arpeggios, and right-hand triads and single-line melodies — echoing a harmonic progression I used in an earlier improvisation (but in a completely different key): Ionian Ghosts.
A reprise of the opening brings the momentum back, fast and unsettling, with the same cycle through B♭ Mixolydian ♭6, G♭ major and B♭ harmonic minor as before, but this time with the G♭ major briefly transforming into G♭ Lydian, just for a very small moment, but enough to subtly brighten the colour. Then the piece resolves with slow, spacious chords in B♭ Mixolydian ♭6.
Some of the ideas in this take feel unrepeatable — the sort of ideas that surface once and vanish, a particular moment in time captured, so I kept it. Whether the slight rhythmic untidiness disqualifies it or defines it, I’m not sure yet. But the tension between rhythmic control and harmonic colour seems to be where this music comes to life.
Modes used and their and Parent Scales
B♭ Mixolydian ♭6 is the 5th mode of the E♭ melodic minor scale. B♭ Dorian is the 2nd mode of the A♭ major scale.
| Mode / Scale | Interval Formula (compared to major scale) | Notes | Parent scale (or relative major) |
| B♭ Mixolydian ♭6 | 1 2 3 4 5 ♭6 ♭7 | B♭ C D E♭ F G♭ A♭ | E♭ melodic minor |
| G♭ Major (Ionian) | 1 2 3 4 5 6 7 | G♭ A♭ B♭ C♭ D♭ E♭ F | – |
| B♭ Harmonic Minor | 1 2 ♭3 4 5 ♭6 7 | B♭ C D♭ E♭ F G♭ A | D♭ major (relative major) |
| B♭ Dorian | 1 2 ♭3 4 5 6 ♭7 | B♭ C D♭ E♭ F G A♭ | A♭ major |
| G♭ Lydian | 1 2 3 ♯4 5 6 7 | G♭ A♭ B♭ C D♭ E♭ F | D♭ Major |
In the end, Triptych in B♭ feels like a meditation on return. The triplet motion that characterises the opening and closing becomes a driving current and a thread, fallible and alive. Each harmonic colour reveals a different facet of the same sound world: the vivid angular light of Mixolydian ♭6, the deeper resonance of G♭ major & B♭ harmonic minor, and the gentle expansiveness of Dorian. Like the three panels of a medieval triptych, the whole is seen only when the parts are held together. However fleeting and unrepeatable the improvisation felt in the moment, its architecture remains: three gestures, three voices, finding coherence through interaction.
I seem to keep returning to the Mixolydian ♭6 mode lately — perhaps because it holds a strange space between light and unease, like a lucid dream that you know you’re inside.
Here are some other improvisations using the Mixolydian ♭6 mode:
Threshold in D – Piano Improvisation Through Shifting Modes
Through Line – Improvisation in C Dorian, C Mixolydian ♭6, and C Lydian Dominant
The following improvisation follows on from Triptych in B♭: Mirror Tetraptych — Improvisation in C Dorian, Phrygian, Mixolydian ♭6, and A♭ major
You might also like Orbit – Improvisation in F Aeolian, D♭ Lydian and A♭ Ionian
Learn more about modes here: Complete Guide to Modes of the Major, Melodic Minor, and Harmonic Minor Scales
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