Based on reprise form. The central section is characterised by the cessation of movement and effusive lyricism. However, the outer parts, though full of movement, weave long-breathed arabesques with tranquility resulting from rocking uniformity and abstract dance. The sound world of the impromptus sound is bright, subject to euphony and beautiful rhythm. Critical source-edition edited by Jan Ekier and Pawel Kaminski based on manuscripts, copies approved by Chopin himself, and first editions. Its purpose is to present the works of Chopin in authentic form. The miniature version of the National Edition does not contain source commentary or performance notes.