Flamenco guitar fingerstyle

Flamenco technique is related to classical technique, but with more emphasis on rhythmic drive and volume, and less on dynamic contrast and tone production. Flamenco guitarists prefer keys such as A and E that allow the use of open strings, and typically employ capos where a departure is required. They often strengthen their fingernails artificially.
Some specialized techniques include:
 

• Picado: Single-line scale passages performed apoyando but with more attack and articulation.
• Rasgueado: Strumming typically done by bunching all the right hand fingers and then flicking them out in quick succession to get four superimposed strums. The rasgueado or "rolling" strum is particularly characteristic of the genre.
• Alzapua: A thumb technique which has roots in oud plectrum technique. The right hand thumb is used for both single-line notes and strummed across a number of strings. Both are combined in quick succession to give it a unique sound.
• Tremolo: Done somewhat differently from the conventional classical guitar tremolo, it is very commonly played with the right hand pattern p-i-a-m-i.

Bossa nova

Bossa nova is most commonly performed on the nylon-string classical guitar, played with the fingers rather than with a pick. Its purest form could be considered unaccompanied guitar with vocals, as exemplified by João Gilberto. Even in larger, jazz-like arrangements for groups, there is almost always a guitar that plays the underlying rhythm. Gilberto basically took one of the several rhythmic layers from a samba ensemble, specifically the tamborim, and applied it to the picking hand.