2 Part Technique - If the opponent posts an arm forward, pull his elbow inside to break his posture. Continue the control and reach behind the opponent's shoulder to lock him into place. Post your foot on his hip, rotate, and lock your other leg high on the opponent's back to completely secure the position. Pass your leg over, control the wrist, and hip up to finish with the most fundamental submission from closed guard. Locking his arms and stacking is generally the most common defense. As the opponent frees his elbow to escape the armbar, swim his remaining arm outwards and attack with the Omoplata. Force the opponent's shoulder to the mat and sit up to complete the shoulder attack.