I. B. Fowler A Bar Chord is a chord shape played making use of the first finger to fret across all the strings.
Bar chords are usually six string chords but can be played in five or even four string versions.
They are used for power and fullness of sound, as well as ease of attaining a large number of chords with a few simple variations of the basic shape. It is then a simple matter to play minor, seventh, sixth, minor sevenths' added ninths and suspended chords by simply removing or adding only one finger. So, as you can see, with a little effort and a sore finger you can know all the chords you'll ever need in about one hour. Pick each string slowly one at a time and listen. To get all the strings to sound clearly Try rolling your finger a little to one side.