Col legno refers to activating the strings “with the wood”, rather than the hair, of the bow. This may be achieved by either “beating” or tapping the strings with the wood in col legno battuto, which results in a percussive, short, sharp attack, or by drawing the wood of the bow across the strings in a typical “stroking action” in col legno tratto, which results in a muted, ethereal timbre.
Col legno battuto is described by Tobias Hume in his viola da gamba piece Harke Harke from his 1605 collection Musicall Humors. The performer is required to “Drum this with the backe of your Bow” (Hume, 1605, p.12). The first known use of col legno battuto on the baroque violin appears in Carlo Farina’s 1627 work Cappriccio Stravagante, where it is described as “here one strikes the strings with the wood of the bow” (Farina, 1627, p. 32). Heinrich Ignaz Franz von Biber employs col legno battuto on the violone in his Battalia from 1673 (Biber, 1673/2007, pp. 3–4). Since this time, col legno battuto appears rarely, yet regularly, in Western art music for modern string instruments, gaining increased application over the post-Second World War period.
Col legno tratto was in use at least as early as the 19th century and into the early 20th century. Like col legno battuto, col legno tratto has been used with increasing frequency in post-Second World War years.
Col legno battuto, col legno tratto on the baroque violin:
Each of these techniques has a similar response on the gut-strung baroque violin as on the steel-strung modern violin. However, the use of various period bows can create a variation in attack with col legno techniques. From my collection of period bows, my preferred bow for col legno battuto is my 17th-century-style short bow, as it has a very articulate attack at the point of the bow. All of my historical bows work well for col legno tratto, particularly my high-baroque bow, as it has a fluted stick whose grooves create a lot of friction between the wood and the gut strings, and therefore a lot of sound.
The following is an example of a G major scale played col legno tratto followed by col legno battuto on the baroque violin with a 17th-century-style short bow.
Video example 4.1 – G major col legno tratto, col legno battuto
The following is an example of col legno battuto and col legno tratto combined with tremolo in Alexander Garsden’s Law II (2013, p. 4).
Video example 4.2 – col legno battuto and col legno tratto passage in Law II by Alexander Garsden (2013, p. 4), bars 130-132
Figure 4.1 – Law II by Alexander Garsden (2013, p. 4), bars 130-132
The following is an example of col legno tratto combined with tremolo in Vincent Giles’ silver as catalyst in organic reactions (2016, p. 3).
Video example 4.3 – col legno tratto in silver as catalyst in organic reactions by Vincent Giles (2016, p. 3), bars 81-82
Figure 4.2 – silver as catalyst in organic reactions by Vincent Giles (2016, p. 3), bars 81-82
Appearing above the intended passages, c.l.b. = col legno battuto, c.l.t. = col legno tratto, as in Figure 4.3 below. Note, for col legno battuto, a staccato marking on the relevant pitch or pitches is further recommended. For notes being played col legno battuto, it can make further sense to use shorter note lengths to represent the actual length of these notes.
Figure 4.3 – example of a possible notation for a col legno battuto passage followed by a col legno tratto passage
 For further discussion of this technique, see Boyden (2001).
 For the surviving original violin part of this piece, which includes the Avertimenti, see Farina (1627, p. 32). The instruction is given in the German, “Hier schlegt man auff die Seiten mit dem Holtze des Bogens”.
 For instance, in Alban Berg’s Lyrische Suite (Berg, 1927, p. 33), Hector Berlioz’s Symphonie Fantastique (1830/1900, pp. 142-44), Gustav Mahler’s Symphony No. 2 “Resurrection” (1897, pp. 38-9), Camille Saint-Saëns’ Danse Macabre (1874, p. 15), various string chamber music by Arnold Schoenberg including his String Quartet No. 4 (Schoenberg, 1939, p. 79), Igor Stravinsky’s Firebird (1910/1933, p. 19), and Anton Webern’s Fünf Sätze für Streichquartett (1922, p. 1).
 For instance, in Richard Barrett’s air (1994), Brian Ferneyhough’s Intermedio alla ciaccona (1986), Helmut Lachenmann’s Toccatina (1986), among many others.
 For instance, in Gustav Mahler’s Symphony No. 1 (1888/1906, p.91), Arnold Schoenberg’s String Quartet No. 4 (Schoenberg, 1939, p. 101), and Anton Webern’s Vier Stücke für Streichquartett (1922, p. 1).
 For instance, in Richard Barrett’s air (1994), and Luigi Nono’s “Hay que caminar” Soñando (1989), among many others.