The research tries to understand the relation between the practice of jiu-jitsu, as developed by the Gracie family, and the violence of the so called pitboys, upper class young boys that often becomes involved in street fights and acts of vandalism. Preventing to approach the subject trough the bias of the absence, normally used to explain the behavior of pitboys - the lack of qualified jiu-jitsu instructors, zealous parents, limits of education, severe laws etc. -, the present study seeks to observe, in the interior of a jiu-jitsu academy, the construction of a warlike ethos, the professionalization of street fights due to the success of No Holds Barred events, the corporal inscriptions of jiu-jitsu practitioners, the importance of the Marias-tatames (young girls who choose only mean jiu-jitsu fighters to date) in the consolidation of a rude style of masculinity, and the relation between virility and masculinity, attributes highly valued by fighters. The research also tries to understand street fights as a game that is part of a playful context; a play that, at the same time, is both rational and irrational, that always implies in some kind of risk and, therefore, in the possibility of recognition for the winners. The wider context in which the phenomenon pitboy came out is also observed: the sensation of unsecurity that is installed in the track of organized crime`s ascension back in the Eighties; the process of identification of pitboys with excluded delinquents; the malandragem culture that joins them both and, paradoxicalally, the frequent use by pitboys of the autoritarian rite do you know who are you speaking to?, that reinforces the distinction between upper and lower class people in Brazil.