The OCS series is a wargame made by..well, you can google it and read all about it yourself. I played a lot of them, from the first Guderians Blitzkrieg, to my favourite Enemy at the Gates, and Tunisia and later...Guderians Blitzkrieg 2. They added a southern part and called the new game Case Blue.
Essentially it is a game of supply. You pay supply to move units that require fuel. You pay supply to shoot. You pay lots of supply to bombard. You dont pay supply to eat, but if you cant trace back to your supply source, then you get to drink the fuel, and eat the bullets by spending your supply. If you cant eat, then you rapidly surrender. As a result, the game is not really one of fighting, but of trying to figure out how to take out the other players supply, and cut him off so he eats his bullets, instead of shooting them at you.
“My logisticians are a humorless lot … they know if my campaign fails, they are the first ones I will slay.” – Alexander the Great