There are very little differences between the official rules and the rules of the OCG. The OCG had a deck composed only of cards with the discipline symbols on them called the "Discipline Deck". The attacking player turns over the top card of the "Discipline Deck" to determine the type of contest between the opposing creatures. The creatures's discipline stats are enhanced or reduced by the battlegear attached, or the location. The players then draw "Power Cards" that have multiples of five printed on the cards. The players take turns to draw power cards which reduce the stat of the selected discipline of the opposing creature. The first player to reduce the selected stat of the opponent's creature to zero is the winner of the battle. These battles continue until one player has defeated all of his or her opponent's creatures. At the end of each battle, if an engaged creature has gained elementals during battle it loses that/those elements.
