Iuna is a composition based on the Berimbau: a traditional single-string Brazilian percussion. This instrument has African origins and it is one of the instruments used in the Afro-Brazilian sport/dance/fight Capoeira, where it has a leading role. During a Capoeira Roda (session) players strongly respond to the instrument and change their dance style / intention based on the music played with the Berimbau. Iuna somehow relates to the sacred connotation of the Berimbau and it should be interpreted as the first appearance of the Berimbau spirit.The compositional process was concerned with a spectral perspective on the sound of the Berimbau. The instrument was recorded and de-composed with various audio analysis tools. Based on this analysis new purely electronic sound were generated and combined with the sound of the instrument, which, in the meantime has been drastically altered - of course.