The hammer-on produces a note artificially by hammering a finger of the left hand onto a string. The impact of the string against the fretboard will cause the string to sound the note of the hammered fret. A hammer-on can be played on either the treble strings or the bass strings.
G
The following example features a hammer-on as part of a bass strum for a G chord.
A popular alternative finger for this chord is to use the 2nd, 3rd and 4th fingers as shown in the diagram. The second finger of the left hand is used to hammer onto the second fret of the fifth string after the open fifth string is played. A hammer-on is indicated by a curved line and the symbol H.
The next song is a traditional Folk song called Crawdad.
The accompaniment to Crawdad uses the bass strum techniques outlined in this lesson. Each chord uses alternating bass notes and bass runs to connect between the root notes. A hammer-on is also incorporated into the accompaniment.