Here is a shape for the A flat / G sharp major guitar chord. This chord diagram uses one of the more common bar chord voicings. The lowest root note of this chord is the Ab / G# on the 4th fret of the 6th string. When a note can be called by more than one name, in this case A flat or G sharp, that note is said to be enhamonic. If you need more help on playing bar chords you can always go to the bar chord lesson.