City War is a mini-pvp event that occurs every weekday on a different city map. The goal of City War is to take the Pole and keep it until the end of the event. The guild who holds the pole at the end of the event will win the current city/map rewards.
Once a guild takes a map, that guild can no longer take any other map for 1 week. However, they can attack and participate in other City Wars (and prevent other guilds from taking those maps). If they win another City War, that city/map will not have a winner.
The event lasts for 30 minutes.
The winning guild members will "own" the map for 1 week. Owning a city map has several benefits.