Let me share with you the 3 improvisations for piano left hand by Frank Bridge.

Some useful musical dates relating to the discussion:

“La Mer” 1905 (first movement "De l'aube à midi sur la mer" / "From dawn to noon on the sea").

Frank Bridge “The Sea” 1911

Three Improvisations for piano left hand 1918

Ravel concerto for the left hand 1929/30

Two definitions:

The first is from Wiki:

Musical improvisation (also known as musical extemporization) is the creative activity of immediate ("in the moment") musical composition….Sometimes …ideas in improvisation are spontaneous, but may be based on chord changes…. One definition is a "performance given extempore without planning or preparation.

The second from the Harvard Concise Dictionary of Music and Musicians:

Impromptu, Impromptu, “in the 19th century and since, is a composition, usually for piano, in an offhand or extemporized style or perhaps intended to suggest the result of sudden inspiration.”

There has been a long tradition of composers being improvisers so it is with some interest that I approached these three works to hear how a meticulous craftsman like Bridge would work his improvisations. The three pieces follow a pattern often heard in the composer’s music, very similar to classical models, an intellectual movement, a slow, lyrical movement and a lively conclusion.

I use the term intellectual with care, all of Bridge’s works are highly crafted and meticulously developed, but the first movements often contain themes that are designed to direct harmony and structure rather than present cantabile melodies which some listeners might expect from his regular use of descriptive titles. This is not to say that the movements are dry or academic, any more than are the first movements of Beethoven sonatas where thematic development is his primary concern.

Improvisers like to use simple harmonic formations like pentatonic scales or modes, and it is with this in mind that I am going to take the last movement “A Revel” first. This movement is of a tocatta style and is easily the most accessible movement of the three. It opens (and closes) with three bars of unambiguous pentatonic music, but quickly moves onto more complex harmonies. There is a lot of repetition of melodic material in chunks, e.g. the opening 7 bars are repeated from bar 15, while the melody in bars 11 and 12 is taken from the pentatonic collection of the opening, but the accompaniment is minor diatonic. The rhythm after the three eighth note opening is dominated by triplet 16th noes until bar 57 where the music reaches its climax (pentatonic), marked brilliante and takes us to the coda. While certain sections are repeated in transposition at a semitone, minor third and fifth this is well within the capability of improvisers, and the introduction of chromatic runs of differing length only adds to the feeling of a good pianist playing with a few fragments of musical material.

Turning our attention to the first movement we have a different story, though at first sight we might make a wrong judgement as “At Dawn” opens with four bars of whole tone scale material. This texture is amorphous, the rhythms make no attempt at forming figures for development, 64th triplet notes require some rubato in performance so that with the arrival of steady semiquavers in bar 6 we might think the music has settled onto its main argument, but this too is preparation for the main melody at bar 11. One can make the argument for main melody based on exposure to his music as Bridge has the tendency to repeat his main melodies in octaves with little or no alteration apart from raised dynamics, as is the case here.

Being able to integrate relatively large chunks of musical material into the music is again well within the range of good improvisers, though the transitions here are very well crafted.

From bar 9 onwards the music is glued together with arpeggio figures flowing from an open fifth, over the long term the harmony is rooted around two fifths E/B and B/F#, which leaves us with the sensation that we are, if not in the key of E, circulating around it. If you examine bars 6 to 8 you will hear that the music is highly chromatic, and even with the pedal notes the music is harmonically restless which gives it the character of more modern music. While the music alternates between different types of harmony the voicing is so well controlled that the listener will hear a continuum and feel cohesion.

Before we leave this movement some mention must be made about the form which is basically very simple but with some interesting characteristics. The introduction falls into two four bar sections, the first dominated by the pentatonic scale, the second 4 bar section confirms through its melodic that we are moving towards E as a tonal point, though the harmony covers 11 of the 12 chromatic notes. Bar 9 takes us to the A section proper, bar 29 repeats the first part of the introduction, A is repeated from bar 33 and 46 takes us to the coda. What is interesting in this journey is that the internal repetitions show the following four chords (represented here as collections and chords based on C) which form the larger part of the music are reversed in their order from bar 36.

0, 2, 4, 6, 8, 10                    (C, D, E, F#, G#, A#) whole tone formation

0, 2, 4, 6, 9                           (C, D, E, F#, A) 

0, 2, 4, 7, 9                           (C, D, E, G, A)  pentatonic

0, 2, 4, 5, 7                           (C, D, E, F, G)

The from bar 36 these formations are reversed but a 0, 1, 3, 5, 7, 9 set occurs just before the whole tone collection, and it should be clear that the penultimate harmony is rich in whole tone steps. If such harmonic control results from coincidence it is surprising, if it is the result of improvisation it could be a fortuitous result or it could be meticulous planning.

The middle movement “a vigil” displays several of the characteristics of the outer movements so I shall refrain from dissecting it and give way to my wife’s comment that a song without words should be taken for what it is. While “At Dawn” seems an appropriate title with its side references to “La Mer” first movement, this title, should we ascribe any value to titles, seems misplaced.  I would have liked to have a metronome mark provided by the composer as taken too slowly the lyrical aspect can be lost, and for me the better performances are those with more rather than less movement, to state the obvious fine gradations can make the difference between an acceptable and a great performance.

These days the term improvisation suggests far greater freedoms than Bridge would have ever considered. Our technologies permit us to play and record, replay and modify, alter timings and durations in such a way that a spontaneous product can be refined into an artistic statement, it may be that like Schubert’s impromptus (set 2)  this is Bridge’s working method but applied in to a more complex harmonic language.