Peterson, Jonathon (2002). "Tuning in thirds: A new approach to playing leads to a new kind of guitar". American Lutherie: The Quarterly Journal of the Guild of American Luthiers. 8222 South Park Avenue, Tacoma WA 98408: USA.: The Guild of American Luthiers. 72 (Winter): 36–43. ISSN 1041-7176. Archived from the original on 21 October 2011. Retrieved 9 October 2012.
Unlike many string instruments which use a bow to create a sound, guitars are played by plucking or strumming the strings on the instrument, which vibrate to create a sound. Chords are played when the guitarist holds their fingers down on more than one individual string to change its length, which in turn changes the frequency of the vibration created - in other words, it creates a different note. Performers often use guitar tabs, rather than sheet music, when learning music: this acts as a kind of 'map' to teach guitarists where to put their fingers on the strings.