I first encountered Guidonian hands as an extension of my interest in graphic scores from the 20th century avant-garde. Beyond their shared use of drawing, and inherent beauty, the two have few conceptual links. Guidonian hands were a medieval mnemonic device (a system of learning aiding retention) designed to assist singers sight-sing (the sung realization of prima vista, or sight-reading). Their development is generally credited to an 11th centruy Italian music theorist named Guido of Arezzo, though the graphic use of the hand as a musical guide long predates the development of his technique. Within a Guidonian hand, each section of the hand indicated a specific note within the hexachord system (six-notes), over three octaves. In the absence of a score, once the graphic hand was memorized by a singer, a conductor would need only point to a series of notes on their hand. They are a fascinating fragment from the development of Western theory, as well as being objects of sublime beauty. I hope you enjoy.