World Championship, the UK Championship, and the Masters together make up the Triple Crown Series, considered by many players to be the most highly valued titles. Although the main professional tour is open to women, female players also compete on a separate women's tour organised by World Women's Snooker. Competitive snooker is also available to non-professional players, including seniors and people with disabilities. The popularity of snooker has led to the creation of many variations based on the standard game, but using different rules or equipment, including six-red snooker, the short-lived "snooker plus", and the more recent Snooker Shoot Out version. History Snooker originated in the second half of the 19th century. In the 1870s, billiards was popular among British Army officers stationed in Jubbulpore, India, and several variations of the game were devised during this time. A similar game, which originated at the Officers' Mess of the 11th Devonshire Regiment in 1875, combined the rules of two pool games: pyramid pool, played with fifteen red balls positioned in a triangle; and black pool, which involved the potting of designated balls. Snooker was further developed in 1882 when its first set of rules was finalised by British Army officer Sir Neville Chamberlain, who helped devise and popularise the game at Stone House in Ootacamund on a table built by Burroughes & Watts that had been brought to India by boat. The word snooker was, at the time, a slang term used in the British Army to describe new recruits and inexperienced military personnel; Chamberlain used it to deride the inferior performance of a young fellow officer at the table. Snooker featured in an 1887 issue of the Sporting Life newspaper in England, which led to a growth in popularity. Chamberlain was revealed as the game's inventor, 63 years after the fact, in a letter to The Field magazine published on 19 March 1938. Snooker became increasingly popular across the Indian colonies of the British Raj, and in the United Kingdom, but it remained a game mainly for military officers and the gentry; many gentlemen's clubs that had a snooker table would not allow non-members inside to play. (Reflecting the game's aristocratic origins, the majority of tournaments on the professional circuit still require players to wear waistcoats and bow ties, although the necessity for this attire has been questioned.) To cater for the growing interest, smaller and more open snooker clubs