A card game of strategy and psychology, poker has gained enormous popularity since the 1990s. It has replaced seven-card stud as the most common form of casino poker, and its no-limit betting format has made it the basis for the televised World Series of Poker (WSOP) and the World Poker Tour. The game also has a strong presence in online gambling.
A variety of games have been referred to as poker, although only those with specific rules that involve betting in rounds and a five-card hand are considered official. The games differ in the number of cards dealt, whether they are face up or face down, and how many are shared by players, but all have the same basic game mechanic.
The earliest known version of poker was played with a 20-card pack that was evenly distributed among four players. The game originated in New Orleans some time between 1810 and 1825, and its gaming milieu was that of French-speaking maritime gambling saloons. It evolved from the earlier vying game of Poque, where one said Je poque to open the betting.
Later games introduced more complicated rules, and it was not until the late 1800s that an authoritative set of rules for poker was published. It was authored by the American ambassador to Britain, General Schenck, and it was accompanied by a booklet of rules for other card games.