11 teams automatically qualify for the event, including the three prior champions:
These teams will compete against four regional qualifiers from the Americas, Southeast Asia, China, and Europe, in addition to the winner of the "Play-In" series, which is made up of the four runner-ups from the regional qualifiers. These regional qualifiers begin May 12 at 12:00 PM EST with the Americas series, ending May 27 with the conclusion of the European qualifier.
Valve's description of the qualifier format says that "In the first phase, each team plays every team once to determine which teams make it to the next phase. The top four teams advance and the other six are eliminated. The second phase is a double elimination best of three format with the 1st and 2nd place teams starting in the upper bracket and 3rd and 4th in the lower bracket. Each Regional Grand Finals is a best of five match."
All this action will lead up to the main event beginning July 18 at KeyArena in Seattle, Washington.