Ludwig van Beethoven's Piano Sonata No. 29 in B major, Op. 106 (known as the "Große Sonate für das Hammerklavier", or more simply as the Hammerklavier) is a piano sonata that is widely viewed as one of the most important works of the composer's third period and among the greatest piano sonatas of all time. Completed in 1818, it is often considered to be Beethoven's most technically challenging piano composition and one of the most demanding solo works in the classical piano repertoire.