[Aesopian]

Andreh Anderson has a solid half guard sweep sequence up on GrappleArts. I am reposting the beginning, where he shows his starting position for easy reference:

This is the starting position. My knee is just over his hip bone and my hands are "checking" his arms to prevent either the underhook or the cross face. I have to thank Ryan Gregg for the detail of the left hand checking the opponent's right arm to prevent the underhook.

If he tries to back out of the position, I can usually get in deep and get the underhook (that foot trap in the next picture is tighter than it looks), but if he forces his way back, I switch to an open guard (usually shins on the biceps).



My feet are hooked in the back like this.



When you feel that you have the opportunity to enter, go for your underhook and drive your left shoulder as close to his right hip as possible.

I underhook and grab the belt, but I am working on changing that grip to my opponent's left trap instead (as per advice Shawn Willians gave me). Grabbing the far trap feels a bit awkward for me, but I need to add it because it prevents him from overhooking your arm and getting the choke.



Now pull your knees forward as you scoot down as much toward his back as you can. You want to be as small as possible so that his hips are over you.

I now initiate the attack and keep the opponent off balance by rocking him. The rocking means I am always trying to get his body higher and higher over my upper body. I want his hips over my chest, if possible, so he feels light and I have an easy path to my knees or his back. I also go for that sweep to my left, and if he bases to prevent it, I rock the other way and the momentum helps me get to my knees.