Major 6th guitar chord shapes

Intervals: 1-3-5-6. A major triad with a natural 6th, strongly associated with swing-era jazz, early standards and guitar comping. On I it is a classic tonic sound and is often preferred over Imaj7 in more traditional or blues-inflected styles (many standards end on I6 or I6/9). The 6th adds warmth and melodic interest without introducing the slight introspective tension of a major 7th. On IV it can act as a relaxed subdominant. In more modern contexts it appears as part of 6/9 sonorities and reharmonisations built from major pentatonic material.