Piano Sonata in F (lost; doubtful), K. 33g
av Wolfgang Amadeus Mozart

The Piano Sonata in F (K. 33g) is a lost and doubtfully attributed keyboard sonata associated with Mozart’s Salzburg years. Often placed among the composer’s juvenilia, it survives only as fragmentary evidence and cannot be securely counted among the authenticated sonatas.
What Is Known
The International Mozarteum Foundation’s Köchel Verzeichnis lists K. 33g as a lost work of doubtful authenticity: a Sonata in F for clavier, with fragmentary transmission and no usable score for performance today.[1] The entry also gives the earlier catalogue cross-reference KV¹ Anh. 202 and assigns the work to keyboard (clavier).[1]
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While older catalogue traditions sometimes associated K. 33g with Mozart’s childhood (and the year 1766), the Mozarteum database dates it more cautiously to Salzburg, 1769–1774—a reminder that even the basic chronology is not fully settled for this doubtful item.[1]
Musical Content
Because K. 33g is lost and transmitted only in fragmentary form, the musical substance cannot be described with confidence beyond the bare identification as a keyboard sonata in F major.[1]
[1] International Mozarteum Foundation, Köchel Verzeichnis entry for KV 33g: status (doubtful/lost), transmission, dating, key, instrumentation, and cross-reference (KV¹ Anh. 202).




