Among important scores that Boulez composes in 1946 (First Sonata, Sonatine, Visage nuptial), is a brief page, Variations-rondeau, officially his first piano score since the withdrawal of the Notations (1945). This short piece will be integrated in 1948 in the Second Sonata, of which it will form the scherzo. Meanwhile, Boulez' language evolves, from an aesthetic close to Jolivet's and a writing system close to Schoenberg's, to a rigor more like Varèse and Webern. Between 1947 and 1952, the composer will therefore several times correct his works, through either a series of stylistic purifications or a rhythmic rewriting in the continuity of Messiaen's reflexions, that he himself develops in his article "Propositions" in 1948. Variations-rondeau is a perfect example allowing to demonstrate this evolution of Boulez' language and the different phases of corrections between the compositions of 1946 and the published scores of 1950. It engages at last the long process in Boulez' work of the perpetually reworking of his scores.