The Adagio sostenuto, F-sharp-minor slow movement of Beethoven's Piano Sonata in B-flat, op. 106, "Hammerklavier" (1817-18), is one of the longest and most complex in the composer's oeuvre. For analysts or commentators tasked with the production of an explication de texte, its challenges are many: tonal, structural, and topical. Merging close analysis with hermeneutic interpretation, this paper argues that one of the most productive entries into this sonata-form movement is through a close reading of its opening 26 measures, the primary theme, largely burdened with the projection of a heavy, grief-leaden desolation. In particular, the tonal and topical implications of that theme radiate through the rest of the movement, which in turn, responding to it, is alternately unsettled and dreamlike, retrospective, or valedictory.

Pursuing this claim, the paper proceeds through three modes of analysis, each of which focuses on a different aspect of the primary theme. The first is tonal, a reflection on the implications of its key, F-sharp minor, construable as a stark and sudden shift away from the B-flat major of the two preceding movements into that key's hexatonic pole, a region of utter darkness. The second is structural, a close phrase analysis that demonstrates the theme's divergence from more familiar, "classical" thematic models. Instead, following a normative eight-bar beginning, the theme becomes caught up in a world of broodingly recursive loops, fleeting visions of escape (the two Neapolitan-chord, G-major projections, historically read as positive but ephemeral visions or moments of transcendence), and the anxieties attendant on the specter of imminent cadential closure. The third is topical, proposing that a generic tradition with which Beethoven's theme is in dialogue (albeit as a "topical deformation") is that of the minor-mode siciliana, which helps to inform its meter, internal rhythms, and harmony, most tellingly in the two mirage-"escapes" to Neapolitan-chord, G-major color. In those passages, though, Beethoven appears to have reversed the traditionally negative affective connotations of the Neapolitan. Speculating on this reversal's entailments leads to a new reading of the tonal interplay at work in the entire movement.