The Adagio sostenuto of Beethoven’s Sonata No. 29, Op. 106, is a long, deeply reflective movement in F-sharp minor. Its opening melody grows from quiet chords and a simple rising gesture. Over the course of the movement, this restrained writing expands into decorated melodic lines, wide-ranging accompaniments, and more active inner voices. Later returns transform the original material before a very soft close.

Opening melody: The movement begins with two rising notes, followed by a chordal phrase marked una corda and mezza voce. The upper melody is supported by bass notes and changing lower chords, while small inner figures connect the harmonies. Short ornaments and quick groups of notes appear as the phrases develop. Some replies enter after rests, and the bass moves chromatically beneath sustained or repeated upper notes. Crescendos briefly strengthen the sound before it becomes quiet again.

More active continuation: An instruction to use all the strings accompanies a somewhat more agitated passage. The left hand alternates bass notes and offbeat chords while the upper line becomes increasingly decorated. Trills, short runs, and groups of different lengths surround the melody. Later, both hands contain moving inner parts, and broken lower figures support a stronger arrival. The music slows before a more tranquil section begins.

Tranquil material and developing texture: Steady lower sixteenth notes support a melody that moves between widely separated registers. Held bass tones and inner notes remain part of the accompaniment. The running motion then spreads between the hands, with one voice answering another through chromatic phrases. Quiet chordal passages recall the opening gesture. Broader left-hand arpeggios and changes between una corda and tutte le corde create further contrasts beneath the upper line.

Decorated return: The main material returns in a much more elaborate form. Continuous upper thirty-second notes outline the melody above regular lower chords and bass notes. Small accents and slurs separate the melodic shape from its surrounding figuration. This passage rises and falls through several waves of activity. The texture later becomes more chordal again while lower sixteenth-note octaves move beneath it. A long slowing leads to a fermata before the offbeat accompaniment and decorated upper line return.

Closing sections: Familiar melodic ideas reappear with altered harmonies and accompaniments. The lower part again supplies flowing sixteenths beneath a spacious upper line, then repeated upper octaves build over quicker lower figures. After this stronger passage, the original chordal material returns quietly. A final growth in sound gives way to sustained upper harmonies over lower triplets. The last phrases recall the rising opening gesture, then settle into softly held chords. A short arpeggiated chord and rests complete the ending.

Interesting fact: The score repeatedly alternates una corda with tutte le corde, making changes of piano color an explicit part of the movement’s design.