The Violin Sonata No. 9 in A major, Op. 47, by Ludwig van Beethoven, is an 1803 sonata for piano and violin notable for its technical difficulty, unusual length (around 40 minutes), and emotional scope. It is commonly known as the Kreutzer Sonata after the violinist Rodolphe Kreutzer, to whom it was ultimately dedicated, but who thoroughly disliked the piece and refused to play it.