In Clash of Clans, a Clan War is a “strategic battle” between two clans. It takes place over the course of two days — a preparation day and a battle day — and provides the winning clan with a large loot bonus. Below are some beginner’s tips explaining how Clan Wars work.
Starting a Clan War
Only leaders and co-leaders of a clan choose to enter a Clan War. You can take your clan to war by opening the Clan War screen and pressing the “Start War” button.
By doing so, this will start the search for an opposing clan. The matchmaking system will ensure your Clan is paired up with a Clan of equal Strength (both attack and defense) and a similar number of Clan members. The War will start immediately after a valid opponent has been found.
Finding an opposing clan can sometimes take several minutes, but you don’t need to wait in the matchmaking screen. If you choose to close the screen, you will be notified when an opponent has been found. You can not challenge specific clans. The warring clan is selected at random from a pool of Clans that match the profile of your Clan.
Participating in a Clan War
To participate in a Clan War, you must be part of a Clan when a leader or co-leader presses the “Start War” button. If you join the Clan after this point, you will become a spectator and will not be able to actively participate in the Clan War.
While you are free to leave your Clan during a War, your War Base will remain visible on the war map even if you leave, so leaving a clan will not affect an ongoing war. Please note that your War Base is not your village and as such all your resources, trophies and even a Shield are not affected by a Clan War.
However, you cannot join another Clan War by joining another Clan, while your original Clan is still battling it out. Other players will be able to see that you are still part of an unfinished war by checking your profile. You will be marked as ineligible for war until the previous Clan War has concluded.
Minimum Clan requirements to go to war
The only requirement is that a Clan must have at least 10 members eligible for war.