The step taken in the Fifteen Hungarian Peasant Songs, where Bartok for the first time began to play around with genuine folksongs rather than merely 'mounting them like jewels', was taken even further in the piano piece that followed the fabulous Studies (and it's going to get a post of its own too) -- the Eight Improvisations on Hungarian Peasant Songs of 1920.
The first Improvisation remains, however, in the easy-going manner of the Romanian Folk Dances. A beautiful folk melody is 'mounted like a jewel' to the accompaniment of fresh, beguiling harmonies in the loveable way that Bartok had been arranging folksongs for more than a decade. It's another one to treasure. What follows is a shock though. A startling dissonance crashes in, like a slap in the face. It takes a few seconds to realise that Bartok is using this as a drone beneath the first statement of the tune of his second Improvisation, which takes us deeper into the new world opened up by the Suite and the Studies. It's still got a catchy folk tune, which it repeats with a few minor (but attractive) melodic modifications, but Bartok plays around with the tempo and ends each repeat with aggressively dissonance 'cadences'.
The third Improvisation is a beauty though, with a dreamy melody. That much is familiar. What's unfamiliar is what happens in the accompaniment, which is now much more than just an accompaniment there purely to serve the folk melody - it's full of interest in its own right, drawing attention to itself as much as to the melody. You'll hear counter melody and a surge of invented melody between the appearances of the tune.
The fourth Improvisation is a 'scherzando' movement that sets a fast folk tune to a lively, characterful accompaniment of ostinatos. Again, you are clearly meant to pay as much attention to the accompaniment as you are to the tune. Even more significantly, the tune itself is subject to variation. It's no longer just the background that changes - and that's if it can even be called 'the background' any more. This process continues in the delightfully tangy fifth Improvisation where the tune is swung through all manner of glamorously dissonant harmonies and then fragmented through variation before a final crunching chord. The sixth improvisation features a variety of types of music within its short frame, from the tartly puckish dancing of the main (rondo-like) theme (which Bartok tweaks as the mood takes him) to the dreamy flute-like melody that soon floats by like a nostalgic memory and the dotted figure that becomes a character in its own right, plus a mysterious interlude near the end.
The seventh Improvisation, dedicated to the memory of Claude Debussy (who had just died), is the star of the set. Its dignified melody is first presented in octaves against a discreet but interesting accompaniment before being set against its own mirror image - a magical, Messiaen-like passage. The closing minute casts it elegiacally against a quiet cloth of bell-like chords. The spirited final Improvisation then bursts in, glinting like silver in the sun. Its tune is then the subject of a short set of variations, including one in the form of a canon - showing a growing interest in counterpoint (which was to become one of the key components of Bartok's later style) - before a splendidly clangy close.
Six years were to pass before another piano work poured forth from the pen of ol' Bela. Then, like British buses, three masterpieces came at once. But that's for another day.