← Bach · Well-Tempered Clavier
Prelude 21 in B-flat major BWV 890
Book II of the Well-Tempered Clavier. Under its figuration, this prelude is 179 chord changes across 88 bars — ranked 14 of 42 by measured difficulty (intermediate) in this survey. 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 →
How it opens
The first changes are IV7 (Bb) · V7/IV (Ab) · IV · I · V7 · iv (Bb) · V (A) · ii7 (Eb) — and the whole prelude keeps moving at roughly that harmonic pace.
What it leans on
Of 178 labeled changes, the harmonies that do the most work: V7 (9×), I (6×), IV7 (G) (6×), ii (6×), V (5×).
Free scores
- Blocked-chord reduction (MusicXML) — the harmony skeleton the player performs
- The prelude as written (MusicXML)