Rasgueado (also called Rajeo or Rasgeo in Flamenco) is a guitar technique employed in classical and flamenco styles of guitar playing, allowing rhythmically precise, and often rapid, strumming patterns to be created.
Flamenco guitarist Paco De Lucia is an example of a player with very advanced rasgueado technique.
Before the 19th century, the terms battuto and golpeado were commonly used to describe the same technique. Although originating in the classic tradition, the technique is most often associated with Flamenco guitar. Andres Segovia tried to remove the use of rasgueado from the classical school, considering it to have been developed "in the noisy hands of the gypsies". Its use in classical music is limited today, but examples of pieces employing rasgueado are Manuel de Falla's "The Miller's Dance" and "Asturias" by Isaac Albeniz. It is also heard in the Rodriguez guitar concerto.
In distinction with ordinary strumming, which is usually done either with a plectrum, or with one clump of fingers at a time, rasgueado generally uses only one digit (finger, thumb, etc) for each strum; this means that multiple strums can be done more quickly than usual by using multiple digits in quick succession. Flamenco guitarists often build up their fingernails using layers of silk and superglue to prevent the nail from breaking. There is some sacrifice of tonal quality in this process, but without it, rasqueado is likely to break most fingernails after a time. The wooden table of the guitar is protected from the reinforced nails by a plastic plate called a "golpe" which is stuck to the front beneath the soundhole.
There are several types of rasgueado, but the two main divisions are those that employ the forearm and thumb in conjunction and those that incorporate only the fingers. Of course, both approaches can be combined to allow for the use of all digits on the hand.
Application of the technique is generally required to achieve the extremely rapid strumming used in flamenco, as well as to play the complex rhythms used in flamenco music. Once learned, the techniques are generally applicable to strumming, and can alter the player's entire approach to strumming and rhythm guitar.