playing, this consists of moving the bow back and forth in very short strokes extremely rapidly, not in precisely measured rhythm (usually at upper half of the bow). Col legno - Occasionally the strings are struck with the stick of the bow ("with the wood.") This gives a muted percussive sound, and is most effective when employed by a full orchestral violin section. The eerie quality of a violin section playing col legno is exploited in some symphonic pieces, notably "Mars, the Bringer of War" of The Planets Suite by Holst as well as Frederic Chopin's Warsaw-era Piano Concerto No. 2, which predates it. Shuffle - A repetitive pattern of slurs and accents, much used in some fiddling styles. Named shuffles include the Nashville shuffle, the Georgia shuffle, and the double shuffle, which is often considered to be a trick or show-off shuffle. Chopping - A more modern percussive technique, in which the hair near the frog of the bow is struck against the strings with a quick scratching sound of indeterminate pitch. It is used predominantly by bluegrass musicians to replicate the off-beat chop of the mandolin however more recently the technique has been embellished by musicians such as Casey Driessen, Darol Anger, and Rushad Eggleston creating cyclical chops and triple chops. Chopping features as a mainstay of many bands arrangements such as Crooked Still, Teho and Turtle Island String Quartet. Straight bow No matter which attack or bow stroke is used, most professional violinists use a straight bow stroke, keeping the bow perpendicular to the string and parallel to the bridge. This ensures that the bow will stay in the desired sounding point and will create a consistent sound quality. One technique to achieving a straight bow is as follows. When taking a downbow, focus on the upper arm, the lower arm, and the hand/wrist. First, move the upper arm backwards as if elbowing someone in the nose. Next, follow through with the lower arm. Near the end of the bow stroke, rotate the wrist and hand as if opening a jar of peanuts. When used correctly, these motions will create a straight downbow bow stroke. A crucial step is to watch the bow and make sure it remains straight. An upbow is created in the opposite way. Still keeping an eye on the bow, move the lower arm in the direction that it came. Follow through with