2 Part Technique - If the opponent is able to get the under hook while you perform the Over/Under Guard Pass, establish the Underhook and Head Control the opposite way instead. Flatten the opponent out and bring your knee across the middle while maintaining the Underhook and Head Control to complete the Knee Across pass. However, if the opponent does not let you establish any underhooks, post with your arms to get a good base. Now, swing your leg over to complete the Back Step Half Guard. The opponent will now expose his far arm for the underhook, so use the Underhook and Head Control while freeing your leg.