Sonaten für Klavier op. 10 Nr. 2 und op. 106 'Hammerklavier' are two piano sonatas by Ludwig van Beethoven, composed and published in 1798 and 1818–1819 respectively. Musically, Op.10 No.2 exemplifies Beethoven's early classical style with concise forms, clear textures and energetic figurations, whereas Op.106 'Hammerklavier' stems from his late period and expands the sonata form into a vast, technically demanding work characterised by wide-ranging dynamics, structural complexity and an extended contrapuntal finale that anticipates later Romantic developments.