Piano Sonata No. 17 in B♭ major, K. 570
di Wolfgang Amadeus Mozart
Mozart’s Piano Sonata No. 17 in B♭ major, K. 570 is a late Viennese keyboard work, composed in February 1789, whose poise and contrapuntal finesse make it one of his most quietly sophisticated sonatas.12 Written when Mozart was 33, it distills an operatic gift for singing line into a texture that often feels like chamber music for two hands.13
Background and Context
By early 1789, Wolfgang Amadeus Mozart (1756–1791) was still based in Vienna, but his public position as a keyboard celebrity had become less secure than in the mid-1780s. The sonata K. 570 belongs to his late cluster of piano sonatas, written after the more dramatic C minor Sonata, K. 457 (1784) and close in time to the final D major Sonata, K. 576 (also 1789).1 In this late period, Mozart’s keyboard writing often turns inward: the virtuoso “public” concerto manner gives way to a more private idiom in which clarity of line, balanced phrasing, and subtle counterpoint do the expressive work.
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K. 570 has also carried a small historical complication: it was first issued posthumously by Artaria (Vienna, 1796) with a violin “accompaniment,” an already old-fashioned marketing category by the 1790s.24 Modern scholarship treats the sonata as fundamentally a piano work; the violin part found in some later editions is generally understood as an added layer rather than Mozart’s original conception.23
Composition
The International Mozarteum Foundation’s Köchel catalogue dates the sonata to Vienna, February 1789.1 The work survives as a completed composition, with autograph source material listed in the Mozarteum’s cataloguing.1 Its dating places it among Mozart’s last substantial solo-keyboard statements—music composed when he had fully absorbed the “galant” legacy of mid-century keyboard style but increasingly enriched it with Haydnesque motivic economy and a keen ear for conversational texture.1
Although the sonata is not attached to a single well-documented premiere event, its clean, idiomatic writing suggests a piece meant to be playable and useful—music for the salon, the study, and the serious amateur, yet with enough compositional nuance to reward the professional. This dual address is one reason K. 570 can be overlooked: it does not advertise its mastery with theatrical difficulty, but rather with proportion, voice-leading, and harmonic timing.
Form and Musical Character
Mozart casts the sonata in three movements, with an unexpected tonal plan that gives the work much of its personality:3
- I. Allegro (B♭ major, 3/4)
- II. Adagio (E♭ major, 4/4)
- III. Allegretto (B♭ major, 2/4)
I. Allegro
The opening movement is a model of late-classical sonata-allegro form (exposition, development, recapitulation) that relies less on virtuoso display than on the elegant redistribution of material between the hands.3 Listeners may notice how often the “melody” is not a fixed top line, but a mobile idea passed between registers—an effect akin to a string quartet’s voice exchange, achieved at the keyboard through careful spacing and imitation.
II. Adagio (E♭ major)
The slow movement shifts to the subdominant (E♭ major), a warm region that Mozart frequently associates with breadth and lyrical ease. Here the sonata’s claim on the listener is its vocality: the right hand sings in long phrases while the left hand supplies a quietly expressive underpinning rather than mere accompaniment. The movement’s restraint—its refusal to overstate—can feel almost “late” in a different sense: it anticipates a nineteenth-century ideal of inward piano cantabile more than it recalls the brilliant Viennese fortepiano showpiece.3
III. Allegretto
The finale, marked Allegretto, returns to B♭ major with a lighter step. Its charm is not superficial; rather, it lies in how Mozart balances playful surface with tight formal control. Many commentators hear a rounded, refrain-like logic here (close to a sonata-rondo manner), where returns are subtly re-colored by what intervenes.3 The result is music that seems effortless—yet that “effortlessness” is precisely the point, a hallmark of Mozart’s mature classicism.
Reception and Legacy
K. 570 has never been as famous as the A major Sonata, K. 331 (with its Rondo alla turca) or the stormier C minor Sonata, K. 457, but its reputation among pianists and scholars is strong: it is often singled out as one of Mozart’s most refined late sonatas, prized for its contrapuntal tact and conversational clarity.3
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Historically, the sonata’s publication pathway contributed to some confusion about genre. Artaria’s 1796 first edition framed it as a keyboard sonata “with violin accompaniment,” a label that encouraged later arrangements and performances that treat it as a kind of duo.24 Modern editions and the Neue Mozart-Ausgabe tradition present K. 570 primarily as a solo sonata, aligning with Mozart’s late keyboard output and with the musical evidence of the piano texture itself.21
For today’s listener, K. 570 deserves attention because it shows Mozart’s mature keyboard art at its most concentrated: a sonata that persuades not by spectacle, but by the steady revelation of craft—how lines interlock, how harmony breathes, and how a seemingly simple B♭-major world can contain an entire drama of balance and shading.
Spartito
Scarica e stampa lo spartito di Piano Sonata No. 17 in B♭ major, K. 570 da Virtual Sheet Music®.
[1] International Stiftung Mozarteum (Köchel catalogue entry): dating (Vienna, Feb 1789), key, authenticity, sources, and links to NMA materials for K. 570.
[2] Neue Mozart-Ausgabe (NMA) Keyboard Sonatas, vol. IX/25/2 — English preface discussing the posthumous Artaria 1796 first edition and the violin-accompaniment framing.
[3] Wikipedia overview for K. 570: movement list (with keys and meters) and notes on the doubtful violin part in some editions.
[4] PTNA Piano Music Encyclopedia entry noting Artaria’s 1796 publication title ‘Sonata with Violin’ and basic work overview.