“Scarlatti - Sonata In D Minor - K.1, L.366” is a three-page keyboard sonata marked Allegro. The music is written in common time with one flat in the key signature, and it has the clear two-part structure often found in Scarlatti sonatas. Both halves repeat. The piece uses fast sixteenth-note passagework, frequent contrasts between f and p, trills, slurred runs, hand-crossing indications, and quick changes between upper-register melody and lower-register accompaniment.

Measures 1–6 introduce the main material with a bold f opening followed by contrasting p and f phrases. The right hand begins with rising sixteenth-note motion and a trill, while the left hand answers with fast broken-note figures and simple bass support. The repeated dynamic contrasts give the opening a lively echo effect.

Measures 7–13 continue the first half with more continuous sixteenth-note motion. A p cresc. marking appears in measure 7, and the music builds toward another f passage. The hands move through quick scale-like figures, broken patterns, and trills before the first half comes to a close with rests and a repeat sign.

Measures 14–17 begin the second half at f. The music starts again with quick running figures, but now the material is shifted into a new register and harmonic direction. The right hand carries fast melodic motion while the left hand supports with broken accompaniment patterns underneath.

Measures 18–22 continue the second half with another p cresc. shape and a strong f arrival. The writing becomes more active, with repeated sixteenth-note patterns, trills, and passing accidentals. The hands move across a wider range of the keyboard, giving this section a more developed and energetic sound.

Measures 23–26 return to material that resembles the opening, again using p and f contrasts with trills at the ends of phrases. The left hand supports with chordal and bass patterns while the right hand plays the fast upper-line figures. This section brings back the recognizable echo-like character from the beginning.

Measures 27–end close the sonata with accented upper notes, quick running figures, and a final p cresc. leading into f. The last measures use fast passagework in both hands and include a hand-crossing indication near the end. The piece finishes with a repeat sign, completing the second half of the binary form.

Interesting fact: Domenico Scarlatti wrote hundreds of one-movement keyboard sonatas, many of them in repeated two-part form. This sonata is listed as K.1 in the Kirkpatrick catalog and L.366 in the older Longo catalog, which is why both numbers appear in the title.