Hello, guys!
Bossa nova is a style of samba developed in the late 1950s and early 1960s in Rio de Janeiro, Brazil.
It's mainly characterized by a different beat that altered the harmonies with the introduction of unconventional chords and an innovative syncopation of traditional samba from a single rhythmic division. The "bossa nova beat" is characteristic of a samba style and not of an autonomous genre. The bossa beat was an extreme simplification of the beat of the samba school, as if all instruments had been removed and only the tamborim had been preserved.
Bossa nova is most commonly performed on the nylon-string classical guitar, played with the fingers rather than with a pick. As in samba, the surdo plays an ostinato figure on the downbeat of beat one, the "ah" of beat one, the downbeat of beat two and the "ah" of beat two.