after a foul, the next player cannot cleanly strike both sides of the object ball, the referee may call a free ball, allowing the player to nominate any other ball in place of the object ball they might normally have played. If a player is awarded a free ball with all 15 red balls still in play, they can potentially make a break exceeding 147, with the highest possible being a 155 break, achieved by nominating the free ball as an extra red, then potting the black as the additional colour after potting the free-ball red, followed by the 15 reds with blacks, and finally the colours. Jamie Cope was the first player to achieve a verified 155 break during a practice frame in 2005, with other players such as Alex Higgins claiming to have made a similar break. One of snooker is called a "frame". A snooker generally consists of a predetermined number of frames. Most matches in current professional tournaments are played as the best of 7, 9, or 11 frames, with finals usually the best of 17 or 19 frames. The World Championship uses a longer format, with matches ranging from the best of 19 frames in the first round to best of 35 for the final, which is played over four of play held over two days. Some early world finals had much longer matches, such as the 1947 World Snooker Championship, which was played over the best of 145 frames. Governance and tournaments Professional Professional snooker players compete on the World Snooker Tour, which is a circuit of world ranking tournaments and invitational events held throughout the snooker season. All competitions are open to professional players who have qualified for the tour, and selected amateur players, but most events include a separate qualification stage. Players can qualify for the tour by virtue of their position in the world rankings from prior seasons, by winning continental championships, or through the Challenge Tour or Q School events. Players on the World Snooker Tour generally gain a two-year "tour card" for participation in the events. Beginning in the 2014–15 season, some players have also received invitational tour cards in recognition of their outstanding contributions to the sport; these cards are issued at the discretion of the World Snooker Board, and have been awarded to players including Steve Davis, James Wattana, Jimmy White, and Stephen Hendry. Some additional secondary