Prelude 4 in C-sharp minor BWV 873

Book II of the Well-Tempered Clavier. Under its figuration, this prelude is 62 chord changes across 62 bars. Played as block chords, it's a progression you can learn in an afternoon; the piece is that progression wearing sixteenth notes.

Practice this piece → Practice chords → Learn it section by section → Hear the harmony →

Opening bars of Prelude 4 in C-sharp minor, reduced to labeled block chords — The opening, reduced: one block chord per change, functional labels above.

How it opens

The first changes are i · v7 (F#) · iiø7 · i7 · III+7 (G#) · iv7 (C#) · i7 · v7 (D#) — and the whole prelude keeps moving at roughly that harmonic pace.

What it leans on

Of 62 labeled changes, the harmonies that do the most work: i7 (5×), i7 (G#) (5×), v7 (F#) (4×), iv7 (C#) (4×), III+7 (G#) (3×).

Free scores

Blocked-chord reduction (MusicXML) — the harmony skeleton the player performs
The prelude as written (MusicXML)