hammer-on

Hammer-on is a stringed instrument playing technique performed (especially on 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 normal fashion are known in classical guitar terminology as legato phrases. The sound is more smooth and connected than in a normally picked phrase. 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 rapid series of hammer-ons and pull-offs between a single pair of notes is called a trill.
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