Chopin's Prelude No. 20 in C minor. Rachmaninoff uses only the first 8 bars plus end-chord, and changes the E♭ in the last chord of bar 3 to E♮.
Variations on a Theme of Chopin (Russian: Вариации на тему Ф. Шопена, Variatsii na temu F. Shopena), Op. 22, is a group of 22 variations on Frédéric Chopin's Prelude in C minor (Op. 28, No. 20), composed by Sergei Rachmaninoff in 1902–03. In the first edition, it is noted that 3 of the variations and the final Presto section can be omitted if the performer wishes.
