https://howtheyplay.com/individual-sports/The-Logsplitter-Biceps-Guard-Opening Opening the closed guard is probably one of the toughest areas of proficiency in all of jiu jitsu. It's incredibly difficult to be inside your opponent's guard -- not a great place to be -- but to have the onus on you to get their legs to open up so that you can advance your position. As a result, a closed guard player must simply remain patient, and wait for the right opportunity to attack. The guard opener, on the other hand, must necessarily risk a great deal in order to open up the guard. However, the "logsplitter" guard opening, involving biceps control, creates one sneaky way around this problem.