Blackball (sometimes written black ball), also known as reds and yellows and English eight-ball, is a pool (pocket billiards) game originating in the United Kingdom and popular across Europe, as well as in some former British colonies such as Australia. In the UK and Ireland it is usually called simply "pool". The game is played with sixteen balls (a and fifteen usually unnumbered ) on a small (6 ft × 3 ft or 7 ft × 3 ft 6 in) pool table with six .
Blackball is an internationally standardised variation of the popular bar and club game eightball pool (a.k.a. eight-ball pool or 8-ball pool), closely related to the originally American and now professionally internationalised game eight-ball. The two main sets of playing rules are those of the World Pool-Billiard Association (WPA, the International Olympic Committee-recognised governing body of pool) and its affiliate the European Blackball Association (EBA), known as "blackball rules", and the older code of the World Eightball Pool Federation (WEPF), often referred to as "world rules" or the "eightball pool rules".
Eightball pool (and thus its standardised form, blackball), like international-style eight-ball, is derived from an earlier game invented around 1900 and first popularised in 1925 under the name B.B.C. Co. Pool by the Brunswick-Balke-Collender Company. Like blackball and eightball pool today, this forerunner game was played with seven and seven , unnumbered (in contrast to the international-style numbered and , sometimes called American-style or kelly pool balls in Commonwealth English), a (numbered "8" or unnumbered), and the white . The game had relatively simple rules compared to the modern game.
The ball sets typically range from 2 inches (50.8 mm) up to 2 3⁄16 inches (56 mm), often with a slightly smaller cue ball, e.g. 1 7⁄8 inches (47.6 mm) for a 2-inch set. The most common sized sets on the market are 2 inches and 21⁄8 inches (54 mm). Along with the single white cue ball, plain unnumbered (or sometimes ) and , seven of each colour, are used in lieu of the numbered and common to international eight-ball and other pool games. Many (especially North American) suppliers refer to the yellows-and-reds sets as "casino" balls, whether UK- or US-sized, because they were formerly used in US casino-hosted, televised, modified-rules eight-ball tournaments popular in the 1970s; the coloured rather than numbered sets were selected for their distinguishability on TV. The , however, still typically bears a number "8" (a holdover from kelly pool), though numberless variants are not unknown.
British pool tables come in 6 × 3 foot (1.8 × 0.9 m) or 7 × 3.5 ft (2.12 × 1.06 m) varieties, with 7 feet being the regulation size for league play. The table has pockets just larger than the balls and rounded, as in the game of snooker, whereas the international-style (or "American-style") table has pockets significantly wider, with pointed .
There are two competing standards bodies that have issued international rules. The older of the two sets in British-style pool are the World Eightball Pool Federation (WEPF) rules (often called "World Rules"). The majority of WEPF members come from the UK and Ireland, and from current and former Commonwealth of Nations countries, plus a few leagues elsewhere.
A competing but very similar set of rules has been promulgated by the larger World Pool-Billiard Association (WPA), under the game name "blackball" to better distinguish it from the American-style game (for which the WPA also promulgates the world-standardised rules). It was intended that "blackball" would unify the various existing British-style rulesets (presumably also including the WEPF rules) although this has not yet happened. The governing body for WPA blackball in Europe, with numerous national and local affiliate groups, is the European Blackball Association (EBA).
WEPF World Rules
The older World Eightball Pool Federation rules pre-date the WPA blackball rules, and remain popular as amateur league rules in the UK, Ireland, Australia, some other Commonwealth countries, and a few European nations. World rules are no longer played at the professional level, since the International Professional Pool Association (IPA) swapped to WPA blackball rules in 2012  Locally the WEPF rules (or minor variants thereof) are sometimes referred to as "British standard pool", "Irish standard pool", etc. As of 2014[update], WEPF leagues exist in: Australia, Belgium, China, Cyprus, France, India, Japan, Malta, Morocco, New Zealand, Ireland, Reunion Island, South Africa, and the UK (with separate leagues in the Channel Islands, England, Northern Ireland, Scotland and Wales).
The balls are racked with (the 8 ball) on the (or "black spot"), in contrast with US-style eight-ball, nine-ball and most other pool games, in which the apex ball is placed on the foot spot. A "fair break" is one in which an object ball is potted, and/or at least 4 object balls contact the cushion. If the black is potted, the game is restarted with a , broken by the original breaker. If the cue ball is potted on an otherwise fair break, it is a "non-standard" (foul) that simply ends the breaker's turn, with no further penalties. If it is a foul (non-fair) break, the incoming player gets as with other "standard fouls" (see below), and gets to break, after a re-rack, without the option to instead play the balls as they lie. Openness of the table (unlike in the American-style game) does not last long, in that if the breaker pots a ball on the break from one group, and elects to continue shooting that group, then that group are his/her balls-on, even if the post-break follow-up shot is missed, while if the group chosen did not have any balls potted on the break, the table remains open until a ball is legally potted. If no balls were potted on the break, the table remains open. The shooter must nominate what group they are shooting for on the shot following the break if they had potted a ball off the break.
A legal (non-break) shot is one where the cue ball first hits a "" (one of the balls in the player's own group), and does not pot the cue ball, the black or any of the balls in the opponent's group, and either one of the shooter's balls-on is pocketed, or a (any) ball contacts a cushion after the cue ball contacts the (first) ball-on. I.e., it is the same as in American-style, but with the additional requirement that one not sink an opponent's ball (doing so is a fault), and lacking the requirement that ball and pocket have to be called (i.e. are perfectly valid, even on the black.) There are other forms of fault, generally the same as in other pool games, such as potting the cue ball (except on the break, as noted above), knocking balls off the table, moving balls accidentally, double-hits and pushes (though the standards are weaker than in American-style rules), unsportsmanlike conduct, etc. There are also other unique fouls such as the requirement (borrowed from snooker) to shoot away from any ball that the cue ball is to, without moving it; however if the frozen ball is the shooter's own, it counts as contacting a ball-on, and only a (any) ball must reach a rail for it to be a legal shot. As in informal American , but not WPA/BCA/IPT standardised American-style rules, players are sometimes required to take certain shots (besides the break shot) from or , i.e. from behind the (). Also, all deliberate jump shots that result in missing an intervening ball are faults.
After a fault, the offending player will effectively miss a turn and give the opponent . These free shots must be taken from where the cue ball finished after their opponents foul, with two exceptions: the cue ball was potted, in which case the incoming player must take their shot from ; or the incoming player has been left in a foul snooker, in which case they may nominate a free ball, move the cue ball to baulk and play from there or indeed carry on as normal (i.e. shoot at one of their own balls).
WPA Blackball World Standardised Rules
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Blackball rules are somewhat similar in gameplay to (though worded differently from) the WEPF World Rules.
Notable differences are:
Unlike in World Rules, deliberate fouls are illegal in Blackball.
'The skill shot'. Blackball Rules enable an opponents ball be potted legally at any time during the frame - provided one of your own colours is also potted during the same shot, this is called a skill shot and is illegal in World Rules.
After a foul in Blackball Rules, the incoming player has one free shot (they may accept the cue ball in-position as it lies on the table, or take cue ball in-hand, and place it in baulk) where they may legally play any ball. Following the free shot, the player will have one visit remaining regardless of the free shot outcome. This is unlike World Rules whereby, following a foul the incoming player will have 2 visits that carry and can only move the cueball in the case of a foul snooker. 
Both the World Pool-Billiard Association (with PPPO and EBA) and the World Eightball Pool Federation currently sanction a World Championship, the WPA version is held every other year. The 2014 WPA World Blackball Champion is Claudio Cassar from Malta, and the 2014 WEPF Eightball Pool World Champion is Tom Cousins from Wales.
- Shamos, Michael Ian (1993). The Illustrated Encyclopedia of Billiards. New York, NY: Lyons & Burford. p. 85. ISBN 1-55821-219-1.
- Jewett, Bob (February 2002). "8-Ball Rules: The many different versions of one of today's most common games". Billiards Digest Magazine: Page 22–23.
- Hickok, Ralph (2001). "Sports History: Pocket Billiards". HickokSports.com: Everything You Wanted to Know About Sports. New Bedford, MA, USA: self-published. Archived from the original on 23 February 2002. Retrieved 13 December 2006.
- Shamos, Mike (1995–2005). "A Brief History of the Noble Game of Billiards". Broomfield, CO, USA: Billiard Congress of America. Archived from the original on 27 January 2007. Retrieved 13 December 2006.
- "World Pool Association [sic] Blackball Rules" Archived February 2, 2007, at the Wayback Machine, World Pool-Billiard Association, 2005.
- "British vs. American Pool". Liberty Games. Retrieved 30 April 2010.
- "World Eightball Pool Federation Eightball Rules" Archived February 23, 2007, at the Wayback Machine, 2004, Perth, WA, Australia
- International Professional Pool Players Association (IPA) — Professional Body for Blackball pool who run a well publicised tour for both amateurs and professionals recognised as the pinnacle for the sport of pool.
- World Pool-Billiard Association (WPA) — world governing body for numerous versions of pool, including "blackball rules"
- World Eightball Pool Federation (WEPF) — international governing body for "world rules"
- UK Blackball Pool — United Kingdom blackball pool resource