Blind from the age of 11, pianist Lennie Tristano became incredibly focused on the purity of sound. He sought, taught, and achieved perfection of tonal expression both in himself and his accompanists (most importantly Lee Konitz and Warne Marsh). He stressed virtuosity devoid of emotional coloration; as such, he remains a controversial figure. His point was to master one's instrument so as to be free from technical constraints, and thereby ably express pure feeling. He had a deep influence on the 1950s cool-jazz school, and his excursions into proto-free jazz left a legacy that has yet to be fully appreciated.