2 Part Technique - If your opponent properly defends you from attaining an underhook to pass his half guard, he may be forgetting to protect his neck from a strong crossface. Wrap your arm around his head, driving your shoulder into the side of his face, while switching your base over to your far hip. Free your knee through his half guard, and plant it across his body into the mount. If he continues to hold his ankle, use the principle of spinal misalignment to weaken his hold on your foot, allowing you to slip it free into the mount position. If you cannot entice him to let go, post your head by his ear on the other side of your underhook, and cross your knee back over to the other side as well for the Knee Slide Pass.