Rigan Machado's Secrets of the Half Guard Rigan Machado is one of the world's foremost instructors of Brazilian Jiu-Jitsu. The half guard is one of the most popular and effective positions in Jiu-Jitsu and mixed martial arts. Put the two of them together and what do you get? The most extensive series on the half guard in the world! Learn locking positions, escapes, reversals, leg locks, attack and defense.