The first movement of the C major, No 50—probably the last of Haydn’s sonatas—is a ne plus ultra of thematic concentration, a brilliant, extrovert counterpart to the strenuous ‘Fifths’ Quartet, Op 76 No 2. It opens with a bald, staccato theme, virtually unharmonized and typically irregular in phrase structure—a vision of dry bones. Haydn immediately repeats and elaborates the theme, initially with full, rolling chords (presaging the orchestral style of much of the writing), then with hints of two-part counterpoint that will have significant consequences later. This single fertile idea reappears, contrapuntally enriched, as a ‘second subject’ (with the theme initially in the bass), and is treated with endless resource in the harmonically breathtaking development. The development’s climax comes with the famous ‘open pedal’ passage, where the once-bare theme is transformed into something rich and strange in the remote key of A flat. What Haydn seems to have envisaged here was not the sustaining pedal, as is sometimes assumed, but the una corda (i.e. soft) pedal available on the new Broadwood instruments but rarely found on contemporary Continental pianos. In the recapitulation the theme attains its lyrical apotheosis with another, more extended ‘open pedal’ passage, now ethereal rather than darkly mysterious.
After a poetically embellished, quasi-improvisatory Adagio in F—a rhapsodic meditation such as we find in many of the late piano trios—the finale is a candidate for the most subversively comic piece that even Haydn ever wrote. A scherzo in all but name, it continually baffles with its lopsided phrases (the quirky main theme consists of five plus two bars), outrageous sudden silences and disorienting feints to absurdly remote keys that, unlike Haydn’s usual practice, remain arbitrary and unexplained to the end.
from notes by Richard Wigmore © 2007