Allegro, ma non troppo: Fast, but not excessively so

This is an improvisatory piece, lasting approximately one minute. The author speculates that it might have been a musical idea initially conceived for a sonata but ultimately rejected. Alternatively, the concept of the trill in this piece might have matured and subsequently led to the moving trill found at the end of Piano Sonata No. 32.

A melodic fragment featuring an air-vibrating trill is repeated four times, echoing as if a reverberation. The cadential figure in measure 5 also finds an echo in the bass in measure 6. From measure 7, the marking "scherzando" (jokingly) appears, where whimsical musical ideas pursue each other in a canonic manner, playfully frolicking. From measure 15, the fantastical opening trill and its echo return, gradually crescendoing from p. As the volume amplifies, the note values in the right hand subdivide and ascend, culminating in an ff arpeggio that rushes downwards as if awakening from a dream, at which point the piece concludes. It could also be interpreted as possessing the character of a prelude. Though brief, it is profound.