col legno
A string technique where the wood of the bow is used to strike or bounce on the strings.
In Depth
Col legno, meaning with the wood, instructs string players to use the wooden back of the bow rather than the horsehair to strike or bounce on the strings. This produces a dry, percussive clicking sound quite unlike the normal bowed tone.
The technique appears in orchestral music when composers want an eerie or skeletal quality. Berlioz used col legno in the final movement of Symphonie fantastique to evoke the rattling of bones, and Holst employed it in Mars from The Planets. Some players are reluctant to use fine bows for col legno, as repeated striking can damage the wood.
Some professional string players carry a second, cheaper bow specifically for col legno passages to avoid damaging their expensive performance bow.