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
Augmented tuning Augmented tuning An augmented tuning is a tuning system for musical instruments that is associated with augmented triads, that is a root note, a major third, and an augmented fifth. The augmented fifth is constructed by stacking the major third with another major third. Consequently, all of the intervals are major thirds. Augmented tunings are used for stringed instruments, especially guitars, and for wind instruments. For guitars, augmented tunings are called major thirds tunings. Major-thirds (M3) tunings are unconventional open tunings, in which the open strings form an augmented triad; in M3 tunings, the "augmented" fifth replaces the "perfect" fifth