Der Jasager (literally The Yes Sayer; also translated as The Affirmer or He Said Yes) is an opera (specifically a Schuloper or "school-opera") by Kurt Weill to a German libretto by Bertolt Brecht (after Elisabeth Hauptmann's translation from Arthur Waley's English version of the Japanese Nō drama Taniko). Its companion piece is Der Neinsager (He Said No) although Brecht's other text was never set by Weill. Weill also identifies the piece, following Brecht's development of the experimental form, as a Lehrstück, or "teaching-piece".