The Nocturne No. 20 in C♯ minor, Op. posth., Lento con gran espressione, P 1, No. 16, KKIVa/16, WN 37, is a solo piano piece composed by Frédéric Chopin in 1830 and published in 1875.
Chopin dedicated this work to his older sister Ludwika Chopin, with the statement: "To my sister Ludwika as an exercise before beginning the study of my second Concerto".[1][2] First published 21 years after the composer's death, the piece is usually referred to as Lento con gran espressione, from its tempo marking. It is sometimes also called Reminiscence.[3] The piece was played by Holocaust survivor Natalia Karp for the Nazi concentration camp commandant Amon Goeth, with Goeth being so impressed with the rendition that he spared Karp's life.[4]
This was also the piece played by Holocaust survivor and famed Polish pianist Władysław Szpilman (the central figure of the 2002 Roman Polanski film The Pianist) during the last live broadcast of Polish radio on September 23, 1939 when Warsaw was besieged by the German army.[5] Years later Szpilman also played this piece for German army officer Wilm Hosenfeld upon their first meeting,[6] though in the corresponding film scene Szpilman plays an abridged version of Chopin's Ballade No. 1 in G minor, Op. 23. Hosenfeld later helped Szpilman hide and provided food to him in the last months of the war.