empty space. Moving a card onto a space occupied by an opponent's card starts a battle! Reveal both cards and do the following for each card type:
If both revealed cards are Creatures/Artifact Creatures, the card with the higher toughness wins and remains face up; the loser is discarded. If they tie, the attacker wins.
Legendary Creatures/Planeswalkers always win against nonlegendary creatures. When they battle each other, the higher toughness or loyalty wins. If they tie, the attacker wins.
If either of the revealed cards is an Instant/Sorcery/Enchantment, discard both revealed cards. (Other effects still happen.)
If one of the revealed cards is an Artifact, the player who owns it discards it and takes an extra turn. If both revealed cards are Artifacts, only the attacker gets the extra turn.
TO WIN:
When a Land is revealed in battle, its owner loses the game. When one Land attacks another, the attacking land wins the game.