After the group has been set, the War League begins, and lasts for eight days.Once a Clan has signed up, they will be placed in a group with seven other Clans in the same league as the Clan.Once every season, there will be a two-day League sign-up period, where Clans can sign up for the War Leagues.Each League runs once per season, at roughly the same time as each other.The highest leagues offer the biggest rewards and show that the clans in them are the best of the best! Supercell described Clan War Leagues as ' Eight Clans Enter, One Clan Leaves' in a youtube video.