The World Snooker Tour is a circuit of snooker tournaments organised by the World Professional Billiards and Snooker Association (WPBSA) for their members. To compete as a professional player, players must be WPBSA members.
Historically a player just needed to become a professional member of the governing body to participate in events, which was attained by formal invitation by an existing current member, and this system was eventually replaced by the "Pro-Ticket" series. The game went open for the 1991/1992 season, whereby anyone could apply for professional membership and enter the tournaments. Due to over-subscription, a two-tiered tour structure was adopted for the 1997/1998 season: the primary tour—known as the Main Tour—with a limited membership, and a secondary professional tour was established for the rest of the professional membership.
The Main Tour consists of ranking tournaments which contribute to a players ranking, and invitational events which do not. All players on the tour can enter a ranking event, whereas the entry criteria for an invitational event is often set by the sponsor or broadcaster, and usually excludes many players on the tour. Ranking tournaments are often played in two stages—a qualification stage and the "main draw", usually at different locations. The main draw is most likely to be held at a prestigious venue where audiences can purchase a ticket and watch the players compete. Typically only the main draw is televised, and therefore often carries considerably higher prize money than the qualifiers. Players traditionally come into ranking events in different rounds based on their world ranking, and the top players in the sport—often the top 16 ranked players—are usually seeded through to the venue stage and do not have to play a qualification match; however, from the 2013/2014 season the circuit began to transition to a "flat" format structure, with all the players starting in the first round. Some tournaments also have an amateur leg that makes it possible for non-members to enter WPBSA events.