Open tunings such as Open G make chord playing very easy, with only one left hand finger needed to play many chords. Here are the power chords in the key of G Major.
Moving that shape down one string produces the "heavier" sounding inversions of those chords. Notice it is the same shape you learned in Lesson 1 (Dropped D tuning), except this time the fifth string is tuned one tone lower, producing different chords .
By adding a note underneath the shapes learned in the previous example you can create some interesting sounds and bass line movement. Try to make up some of your own combinations.
The great thing about Open G tuning is that when you bar one finger across all six strings, it creates a complete chord. It is the easiest chord shape to remember. Slide guitar players use Open G and Open D.
Knowing that a barred shape will produce a chord, we can now play with that simple shape by picking fragments of it, rather than playing all six strings simultaneously. By playing "fragmented chords" your riffs will sound better, and your fretting hand will be free from an otherwise rigid position. This will enable your other fingers to reach for other notes outside the bar shape, and will help you find interesting harmonic movement.
The following example shows the use of fragmented chords, and reaching for notes outside the bar shape. With the exception of one chord, the entire riff is playable with a single finger.
Blues guitarists have often used open tunings, mostly for the ease of playing that these tunings afford, and the unique tonal qualities that come from open strings.
Keith Richards from The Rolling Stones is a masterful player in Open G tuning. Many of the band’s hit songs showcase the ability of open tunings to produce great riffs with minimal hand movement.