Often it becomes necessary to hold down more than one string and as many as six, and this is achieved by the use of the full Bar and half Bar. As demonstrated in the following photos, the entire first finger (1) is used to form the full Bar which covers all six strings, whilst only the tip segment of the first finger is used to cover any combination of three adjacent strings, in this case #@ and ! to form the half Bar. Make sure to keep the first finger perfectly straight, and close to the fret whilst executing the full Bar, in order to produce clear notes on each string without buzzing. Carefully study the photos of the half Bar as the angles and curves need to be correct, in particular the almost pyramid structure of the middle joint in photo D. Be sure to retain a chromatic left hand position and avoid bunching fingers during the use of the full and half Bars.
Note that the wrist is pushed out by the use of the full Bar (photo A and C) and that the thumb drops closer to the treble side of the fretboard.
For example:
B3 means to use the full Bar across the third fret.
1/2 B5 means to use the half Bar across the fifth fret.