Here are some of the "airplane notes" I took while re-reading Eddie Bravo's Jiu-Jitsu Unleashed:
1. LOCKDOWN
--the inside leg is essentially straight
--the outside leg loops over the opponent's outside leg at the knee
--the inside leg goes OVER the foot of your outside leg; the foot on the inside leg goes UNDER the ankle of the trapped leg
--the knee of the outside leg will point up and out--almost as with a butterfly guard
*To complete the Lockdown, straighten your legs
--this will put distracting pressure on the opponent's calf muscle
--this will also help undermine the base on the side of the trapped leg
2. DOUBLE UNDERHOOKS AND HEAD/BODY POSITION
It is most important to get the underhook on the lockdown side.
Gable grip either right below the shoulder blades and right above the small of the back. Adjust depending on the leverage you need.
With regard to head/body position:
--Always be on your side, tilting into the guy ... You don't want your ass fully on the mat, at least not for extended periods. There is no leverage from the position to sweep (although you can set up attacks like the Apollo Arm Triangle from flat on your back) ...
--Your forehead shouled be no higher than the guy's pecs/mid-chest when working most sweeps from half-guard. Concentrate all of your body to attack against 3/4 or half of his.
3. SWEEPS
One common feature in Bravo's half guard sweep is the move to both knees, facilitated by coming up on the elbow of the non lockdown side. Use the lockdown side underhook to help control the opponent's body and get leverage. Maintain outside leg "overhook" of the trapped leg (sort of an "open half guard") as long into the sweep as is necessary.
Bravo's sweeps can be divided into two types:
Tackles: Old School, Half and Half, Half Quarterback Sweep
Twists: Plan B. Twist Back, Half and Twist, Quarter Twist Back
The key detail in the Tackles seems to be coming up on that far side elbow and knee. "Far side" sounds off, because as you move, that elbow and knee actually come behind where the lockdown side was. Maybe I'll call it the "free" side ...
Old School has you grab the far foot (palm up, so you're maximing your effort by using your back instead of your shoulder) and "tackle" the guy over. Both the Half and Half and the Half Quarterback Sweep are more "pure" tackles, with the key detail being that you want to circle around toward the guy's lower body, rather than trying to just plow through him. You want to make sure when doing the last two Tackles is that you want to avoid fighting through the post arm.
The key detail in the Twists seems to be loosening your outside, looping, leg a bit, and hooking your inside leg ("free" leg) inside the crook of the near knee. This position will be the main "fulcrum" when you re-establish the double underhooks (they were released so that you could escape your hips out and come up on the free elbow and knee), and literally "twist" the guy backward over your foot-in-crook-of-knee
