The StarCraft II World Championship Series (WCS) was a StarCraft II professional tournament series organized and sanctioned by Blizzard Entertainment that ran from 2012 to 2019. For all but its first year of operation, it was the highest tier of professional StarCraft II competition. Its longest-running iteration featured two regions, World Championship Series Korea and World Championship Series Circuit, with World Championship Series Global events featuring players from both regions. Grand finals were held annually at BlizzCon in Anaheim, California, except for the first year of competition, when the finals were held in Shanghai, China. WCS Circuit events were streamed on Twitch while WCS Korea events were available on Twitch, YouTube, and afreecaTV.