A Bar chord has no open strings and can be played anywhere on the fretboard. The first finger of the left hand is used to Bar across all six strings of one fret and the other fingers are used to form the chord shape as shown in the following photographs of the G major and C major Bar chords.
Bar chords are based on open chords, e.g., This root 6 G chord is an open E major chord played after a Bar across the 3rd fret.
This root 5 C chord is an open A major chord played after a Bar across the 3rd fret.
Bar chords are commonly used in Pop, Rock and Blues music and when played on an electric guitar with loud volume and amplifier distortion Bar chords (and parts of Bar chords called power chords) are the basis of heavier rock styles, e.g., Heavy Metal. Bar chords are easier to play on an electric guitar but are also played on acoustic guitars. Bar chord shapes are called Movable shapes because they can be played with the first finger bar on any fret, e.g., if the G major Bar chord shape was moved two frets higher it would be an A major chord. Before studying Bar chords you should be familiar with the most common open chord shapes as shown in Appendix Three. These chords are introduced in Progressive Guitar Method: Rhythm which also contains chord progressions and strumming rhythms to practice these chords with.