What is the point of the guard?
The idea of the guard is to control your opponent’s body. Generally, you establish this control with your legs. In a closed guard, your legs are around your opponent’s body, controlling him by the hips. In an open guard, you are controlling other key parts of his body. For example, in the spider guard you are controlling both arms by gripping the cuffs and putting your feet in his biceps. This controls the opponent by controlling his upper body. In the modified spider guard, you are also controlling both arms by gripping the cuffs. But instead of putting your feet on his biceps, you bring him closer and press your knees against his biceps.
The butterfly guard is another guard worth mentioning—though it mostly appears to be a transition guard. Here both your feet between the opponent’s legs, right under his groin. At the same time, you pull his body close to yours. This guard is the epitome of keeping your legs between you and your opponent—because with this guard, that’s all you’ve got! That said, having your legs in this position does give you a lot of leverage to take the opponents over your back or over to one side.
The X guard is an exotic guard that Marcelo Garcia has used to great effect. In this guard you control the lower body by controlling the thighs and legs. Both feet are used as hooks on the same leg. Here is the description from Grapplearts.com with my notes in italics.
His foot is up on my right shoulder, not in the crook of my arm.
My right leg inserts through his legs and my right instep is nestled in the crease of his hip. My right knee is behind the plane of his body underneath the thigh of the opposite leg.
My left leg is positioned so that my instep hooks behind his right knee, pushing it away from me.
My right hand cups his leg, typically controlling it at the kneecap.
They add about the X guard that it is an effective move from the butterfly guard, as often the opponent will try and stand out of the butterfly guard, opening himself up to the X guard trap.
The idea of sweeping from the guard is two-fold: control the cuffs or the collar, and try and get the opponent’s weight on your hips where it will be easier to control him. There are three main options: taking the guy over your back, taking him to your right, and taking him to your left. All non-attacking moves from the guard should be geared toward one of these three objectives.
