Each round, you and the enemy flip the top card of your deck. Whoever's card is higher wins both cards, which go to the bottom of the winner's deck.
War!
If both cards match in rank, it's a War: each side places two cards face-down, then draws one more card to decide it. Whoever's new card is higher takes everything on the table — including the face-down cards. A tie on that card chains into another War.
Winning
The game ends when one side has collected all 52 cards.