Guitar chord in the abstract musical-theory of chords for all instruments. For example, in the guitar (like other stringed instruments but unlike the piano), open-string notes are not fretted and so require less hand-motion. Thus chords that contain open notes are more easily played and hence more frequently played in popular music, such as folk music. Many of the most popular tunings—standard tuning, open tunings, and new standard tuning—are rich in the open notes used by popular chords. Open tunings allow major triads to be played by barring one fret with only one finger, using the finger like a capo. On guitars
Tuning mechanisms for stringed instruments there is not space for a knob on each string, such as pianos and harps. Turning the peg tightens or loosens the string, changing the pitch produced when the string is played and thereby tuning it. A pegbox is the part of certain stringed musical instruments (violin, viola, cello, double bass, lute) that houses the tuning pegs. A tapered peg is simply a smooth peg with a string wound around it. The tension of the string is controlled by turning the peg, and the peg is held in place by friction in its hole (in contrast to tuning machines, below).