Distance control and half guard: One of the great associated with the use of half guard is that of DISTANCE CONTROL. Your opponent in position will usually be looking to get right chest to chest and control your head and . If he can do so you will have almost no means of controlling the distance between yourself and your opponent for the simple reason that you will have no means of PUSHING WITH YOUR LEGS TO CREATE SPACE. Once an opponent get to half guard chest to chest, your legs can only PULL. One way to combat this problem is the use of an initial knee shield using the knee of your top leg positioned at the hip or sternum. This gives you what you need to control distance – the to use a leg to push and create space. This can be used to halt your opponent's initial drive, and then to your the space needed to come up with an underhook around your opponent's waist that will create an attacking half guard position where your opponent will not be able to establish control over your head and shoulders. Used well, that knee shield can give you the attacking half guard you seek rather than strong position on top that your opponent seeks. As a general rule I like to position my knee shield at the hip when working without the gi, and at the sternum when I can reinforce it with my collar grip with the gi. Play around with the knee shield as a means of initially controlling distance so you can get the half guard positioning YOU want rather than the one your OPPONENT wants!