No Haydn sonata is more indebted to Emanuel Bach’s brand of Empfindsamkeit
—the language of heightened sensibility that had its literary roots in the works of Jean-Jacques Rousseau and the German poet Klopstock—than the Sonata in A flat, No 46, composed around 1767–8. Beyond any specific influence, this beautiful work reflects the striking intensification of Haydn’s musical idiom in the years immediately following his elevation to full Kapellmeister at the Esterházy court in 1766. Opening with a typically empfindsamer
theme, irregularly phrased and characterized by delicate ornaments and sighing appoggiaturas, the first movement surpasses all its predecessors in scale, expressive richness and variety of rhythm and texture. As so often in Haydn’s earlier sonatas, the central section is more a free fantasia than a true development, though here the exhilarating toccata-like figuration sweeps through an unusually adventurous spectrum of keys.
For the Adagio, Haydn moves to the subdominant, D flat major, an outré key in the eighteenth century and one never used by Mozart. With the extreme tonality goes a peculiar intimacy of expression: from the delicate contrapuntal opening, with the bass descending passacaglia-style, this is one of the most subtle and poetic of all Haydn’s slow movements. The polyphonic and chromatic enrichment of the main theme in the development suggests not so much C P E as J S Bach at his most inward; and Haydn opens up further strange harmonic vistas in the coda. With its catchy, quicksilver main theme, the compact sonata-form finale provides a glorious physical release. Yet for all its exuberance this is no mere frothy romp. The darting semiquaver figuration always has a strong sense of direction, above all in the powerful chromatic sequences just before the recapitulation.
from notes by Richard Wigmore © 2007