Blackball (sometimes written black ball or black-ball) is a pool (pocket billiards) game that is popular in the United Kingdom, Ireland, several Western European nations, Australia and some other countries. In the UK and Ireland it is usually called simply "pool". The game is played with sixteen balls (a cue ball and fifteen object balls) on a small (6 ft x 3 ft or 7 ft x 4 ft) pool table with six pockets. Blackball is an internationally standardised variation of the popular bar and club gameeight-ball pool (a.k.a. 8-ball pool or eightball pool), closely related to the originally American and now professionally internationalised gameeight-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".