Bowed string instruments are instruments that are mostly played with a bow. The most common representatives are the violin, viola, cello and the double/upright bass. String instruments have a long tradition in orchestral music and are the leading instruments in classical music. The oldest representative of this group of instruments is the musical bow that was already in use 15.000 years ago.
The sound of bowed string instruments is usually generated by bowing and is caused by a stick-slip phenomenon. In contrast to plucking it is possible to produce long, sustained tones. In order to intensify this effect, rosin is applied to the hairs of the bow. There are various techniques of bowing like legato (tones are tied together), spiccato (the bow is removed from the string after each draw), or long draws that remind of the sound of the human voice. Plucking is a technique that is used to create a certain sound and has become the most common style of playing the double bass in jazz music.
Bowed string instruments, as opposed to other stringed instruments like the guitar are not fretted and therefore it is possible to play micro intervals (intervals that are smaller than a half tone step). Proper intonation is key for playing and along with correct bow positioning and drawing techniques constitutes a considerable obstacle to learning these instruments.