Hammer-on

Hammer-on is a stringed instrument playing technique performed (especially on fretted string instruments such as guitar) by sharply bringing a fretting-hand finger down on the fingerboard behind a fret, causing a note to sound. This technique is the opposite of the pull-off. Passages in which a large proportion of the notes are performed as hammer-ons and pull-offs instead of being plucked or picked in the usual fashion are known in classical guitar terminology as legato phrases. The sound is smoother and more connected than in a normally picked phrase, due to the absence of the otherwise necessity to synchronize the plucking of one hand with the fingering on the fretboard with the other hand; however, the resulting sounds are not as brightly audible, precisely due to the absence of the plucking of the string, the vibration of the string from an earlier plucking dying off. The technique also facilitates very fast playing because the picking hand does not have to move at such a high rate, and coordination between the hands only has to be achieved at certain points. Multiple hammer-ons and pull-offs together are sometimes also referred to colloquially as "rolls", a reference to the fluid sound of the technique. A hammer-on is usually represented in guitar tablature (especially that created by computer) by a letter h. A rapid series of alternating hammer-ons and pull-offs between a single pair of notes is called a trill.