123Movies. “Piano Lessons” is a feature-length documentary which tells the story of the “underground hero”, German Diez Nieto, pianist and pedagogue, an under-discussed cultural hero of Western society, whose teaching touched and informed generations of musicians. The documentary tells the story of his compelling life, and in doing so, bears witness to the importance of Diez’s legacy: a tradition of music making passed down from Beethoven, through Czerny, Liszt and Arrau, directly to German.