Plucking
Plucking (Italian: Pizzicato) is used as the sole method of playing, on instruments such as the guitar, oud, sitar, banjo, lute, mandolin and harp, either by a finger or thumb, or by some type of plectrum. This category includes the keyboard instrument the harpsichord, which formerly used feather quills (now plastic plectra) to pluck the strings.
Bowing
Bowing (Italian: Arco) is a method used in some string instruments, including the violin, viola, cello, and less commonly, the double bass (of the violin family) and the old viol family. The bow consists of a stick with many hairs stretched between its ends. Bowing the instrument’s string causes a stick-slip phenomenon to occur, which makes the string vibrate.
Other bowed instruments are the rebab, rebec, hardingfele, nyckelharpa, kokyū, erhu, igil, kamanche, and sarangi. The hurdy gurdy is bowed by a wheel.
Striking
The third common method of sound production in stringed instruments is to strike the string with a hammer. By far the most well-known instrument to use this method is the piano (sometimes considered a percussion instrument), where the hammers are controlled by a mechanical action; another example is the hammered dulcimer, where the player holds the hammers.
A variant of the hammering method is found in the clavichord: a brass tangent touches the string and presses it to a hard surface, inducing vibration. This method of sound production yields a soft sound. The maneuver can also be executed with a finger on plucked and bowed instruments; guitarists refer to this technique as a hammer-on. After the invention of electric pickups guitars could be played solely by hammer-ons. Since both hands then can be used it is often called “two-handed tapping”. Guitar-/bass-like instruments are being manufactured mainly for this purpose, like the Bunker Touch Guitar, the Chapman Stick, the Warr Guitar and the Megatar.
Violin-family string instrument players are also occasionally instructed to strike the string with the side of the bow, a technique called col legno. This yields a percussive sound along with the pitch of the note. A well-known use of col legno for orchestral strings is the Gustav Holst’s “Mars” movement from The Planets suite.
