Allegro in F

The London Sketchbook (K. 15a–ss) is the notebook Mozart filled in 1764–65 while in London at the age of eight — small dance movements, song fragments and study pieces that a child prodigy used to work out his ideas. The Allegro in F, K. 15a, is one of the most polished entries: a complete miniature in binary form, simple textures, and the unmistakable Mozartian instinct for periodic phrasing already audible in a child's hand.

Technically the piece tests two skills the earlier Köhler does not press as hard: a confident two-hand texture where each hand has a real (not Alberti) line, and the small cadence ornaments that mark Classical style. The right hand carries the melody; the left hand walks in step-wise crotchets and quavers rather than in a broken-chord pattern. There are simple repeats and a return.

Two pitfalls. First, students play it like a sonatina by Köhler — Alberti-style — when the left hand here is more a walking countermelody than an accompaniment. Listen for the inner-voice motion in the bass and let it speak. Second, the cadence ornaments (turns and short trills) are sometimes hurried into the next bar; keep the trill within its beat and let the harmonic resolution arrive on time.

Listening: any clean PD recording of the London Sketchbook (Musopen has historical recordings) calibrates the right Mozartian poise — these are not concert sonatas but they have the lineage in them.