Most versions of the game use it, but there are a few exceptions. The most notable is lowball, where the lowest hand wins. Seven-card stud and Texas hold ’em (or just “hold ’em”) use the standard ranking.
Poker’s unpredictable process of determining a winner is what separates genuine poker versions from the downpour of quasi-poker games that have flooded the market in the past few decades.
Video poker, Caribbean Stud Poker, Let It Ride, and all the other recent inventions have an absolute standard for winning and losing. You can read it on a pay table. Real poker has no such thing. No hand is an automatic winner (besides a royal flush), and no hand is an automatic loser.
In fact, the object of poker is not necessarily to have the best hand. The object is to win the biggest pot (the combined bets of all the players).
Having the best hand may allow you to do that, but it may not. Keep this in mind as we explain how the game works.
Obviously, the best hand wins in a showdown. That’s when two or more people reveal their hands to see who will win the pot. If two players have identical hands (two flushes, two straights, two full houses), the rank of the cards in each hand will determine the winner.