Nine-ball is a contemporary pocket billiars (pool) game, with historical beginnings rooted in the United States and traceable to the 1920s. The game may be played in social and recreational settings by any number of players (generally one-on-one) and subject to whatever rules are agreed upon beforehand, or in league and tournament settings in which the number of players and the rules are set by the sponsors. During much of its history, nine-ball has been known as a "money game" in both professional and recreational settings; but today, in major tournament settings, it is respected and remains the dominant game (although ten-ball is gaining momentum).