On the berimbau
The berimbau is a one-stringed bow-shaped instrument with a gourd as a sound chamber, played with a stick and a coin or stone and accompanied by a rattle called a caxixi. In addition to being an inseparable part of Capoeira, it has been transformed into a unique addition to percussion sounds in world music by artists like Naná Vasconcellos, and learning to play it is as deceptively simple as the art of Zen archery. In other words, it can take a lifetime to master, and only a few, like João Grande, achieve such mastery.
Read more about it on Wikipedia