GRACIEMAG.com: Black belt world champion Otávio Sousa teaches a wrist lock attack December 5, 2012 by Gary Berger Leave a Comment 2012 IBJJF world champion Otávio Sousa teaches a wrist lock attack from the back. He has the help of purple belt Frank Nava. This is an exclusive position for GRACIEMAG Newsletter subscribers. 32 2