winning the World Championship seven times (1990, 1992–1996, and 1999). Ronnie O'Sullivan has won the most world titles since 2000, having done so on seven occasions (2001, 2004, 2008, 2012, 2013, 2020 and 2022), while John Higgins and Selby have both won four times (Higgins in 1998, 2007, 2009, and 2011; Selby in 2014, 2016, 2017, and 2021), and Mark Williams three times (2000, 2003, and 2018). O'Sullivan is the only player to have made 1,000 career century breaks, and holds the record for the most maximum breaks compiled in professional competition, having achieved his 15th in October 2018. O'Sullivan also holds the record for the most ranking titles (39) and most Triple Crown titles (21) achieved in the sport. Variants Some versions of snooker, such as six-red or ten-red snooker, are played with almost identical rules but with fewer object balls, reducing the time taken to play each frame. The Six-red World Championship, contested annually in Bangkok, Thailand, has been a regular fixture on the World Snooker Tour since 2012. The ten-red game has had a World Women's 10-Red Championship held annually in Leeds, England, from 2017 to 2019. Geographic variations exist in the United States and Brazil, while speed versions of the standard game have been developed in the United Kingdom. American snooker is an amateur version of the game played almost exclusively in the United States. With simplified rules and generally played on smaller tables, this variant dates back to 1925. Sinuca brasileira (or "Brazilian snooker") is a variant of snooker played exclusively in Brazil, with fully divergent rules from the standard game, and using only one red ball instead of fifteen. At the start of the game, the single red is positioned halfway between the pink ball and the side cushion and the break-off shot cannot be used to pot the red or place the opponent in a snooker. The Snooker Shoot Out is a variant snooker tournament, first staged in 1990, featuring single-frame matches for an accelerated format. The idea was resurrected in 2011 with a modified version that was added to the professional tour in the 2010–11 season and upgraded to a ranking event in 2017. Other games were designed with an increased number of object balls in play. One example is "snooker plus", which included two additional colours: an orange ball worth eight points positioned between pink and blue, and a purple ball