Clawhammer is a highly rhythmic and common component of American old-time music. The principal difference between clawhammer style and other finger picking styles is the picking direction. Traditional picking styles, including those for folk, bluegrass, and classical guitar, consist of an up-picking motion by the fingers and a down-picking motion by the thumb; this is also the technique used in the Scruggs style for the banjo. Clawhammer picking, by contrast, is primarily a down-picking style. The hand assumes a claw-like shape and the strumming finger is kept fairly stiff, striking the strings by the motion of the hand at the wrist and/or elbow, rather than a flicking motion by the finger. In its most common form on the banjo, only the thumb and middle or index finger are used and the finger always downpicks, hitting the string with the back of the fingernail or a pick.
Modern musicians who have used the clawhammer style of picking include Bob Carlin, Dwight Diller, Eric Clapton, Ken Perlman, Dan Levenson, Brad Leftwich, Mark Johnson, Dick Kimmel, Michael J. Miles, Abigail Washburn and thousands of others. Actor/comedian Steve Martin played clawhammer banjo as part of his stage act in the 1970s. In fact there are probably more clawhammer players today than there ever have been, thanks to exploding population and widespread references in media. Early practitioners include Clarence Ashley, Tommy Jarrell, Kyle Creed, and Wade Ward.
Here, the thumb plays the high drone on the second "and" of "one and two and". This combined with the middle finger strumming provides a characteristic "bum-ditty bum-ditty" banjo sound, whether actually played on a banjo or on a guitar.
Banjo players often also use the left hand, the fingering hand, to pick. Using a motion similar to a pull-off, the left hand picks up at the top of the neck, usually on the second half of the first beat. The result is a change from the "bum-ditty" sound to a "bum-pa-ditty".
Confusing the nomenclature further are the terms that are used for perceived variations on the method. These include "flailing," "knockdown", "banging," "rapping," "beating," and "clubbing." This is reflective of the informality of old-time music in general, as each player develops an idiomatic style.
Some have noted a general tendency towards more traditional and rhythmically-oriented frailing styles in the South, particularly in North Carolina, and a general tendency towards more melodically intricate styles in New England. The clawhammer banjo style of Boston banjo virtuoso Ken Perlman, for example, is highly melodic and uses the thumb extensively to play long single-note lines that use the drone string more for melody notes than for rhythmic accent. However, some clawhammer banjo aficionados (including Perlman) have argued that melodic clawhammer banjo techniques are more traditional and ancient than many advocates of the frailing style suppose.
Another usage of "clawhammer" in guitar circles refers to a style in which the pinky finger or the pinky and ring fingers are used to brace the hand and the index finger, middle finger, and thumb are used to pluck the strings. The index and middle fingers are held in a claw shape and they do resemble the two prongs of a claw hammer, but this is an uncommon and arguably incorrect usage of the term "clawhammer". See fingerpicking.
Mark Knopfler of Dire Straits used a variant of the clawhammer technique. In recent years, the clawhammer technique has been applied to playing bass. Examples include Michael Todd, of Coheed and Cambria, and Steve Parker of Elements of Refusal.
Frailing banjo instructional video series on archive.org.