Contrary to what many people believe, the “show one, show all” rule is not really about the cards per se. It does not mean that if, for whatever reason, you expose one of your hole cards that you will then be obligated to show both of them. The “one” and “all” in this rule are people; if you show one person at the table your cards, then you must be willing to show your cards to everybody. This is one of those universal poker rules, enforced in cardrooms everywhere. But as with virtually all poker rules, the details of exactly how it gets interpreted and enforced vary from one venue to another.
 
The point is simply to ensure fairness to all players in the game. It’s quite common in a live poker game for a player (let’s call him Mr. Exhibitionist) to intentionally flash his cards to a neighboring player (whom we’ll dub Mr. Witness), after Mr. Witness is no longer in the pot. Most of the time this poker peekaboo happens at the conclusion of the hand, in the moment just before Mr. Exhibitionist mucks his losing cards. At first blush, this can seem like a very innocuous thing to do, since Mr. Witness is no longer involved in the hand—and in all likelihood, never expressed any desire to see the exhibitionist’s cards in the first place. It’s just a brief little peek at a couple of cards no longer in play, so no harm no foul, right?
 
The harm comes from the fact that Mr. Witness is now privy to information that the rest of the players at the table didn’t get a chance to find out. Because of his neighbor’s little peep show, Mr. Witness now knows a little something extra about this opponent, about the way he played those particular cards during the previous hand. It may be only a tiny kernel of information. It may even prove to be ultimately useless information. But the mere fact that one player knows it while the rest of the players in the game never even got a chance to learn about it, is patently unfair.
 
In poker, any information about your opponents, about the way they play, is a precious commodity. It’s gold. In that sense all poker players are prospectors, constantly mining for nuggets of information about the way our opponents play—information we can later use to beat them. The best players are supremely talented prospectors who can locate a strand of gold in any poker face, even if it appears to be carved out of pure granite, while other players wouldn’t know a 24-karat ingot if it fell on top of them. But the opportunity to find this information, this gold, should always be distributed evenly between the players. It simply isn’t fair for one player to receive a free little nugget that nobody else gets to have.
 
Because of the “show one, show all” rule, any player at the table who realizes this has happened can request to see the exhibitionist’s cards at the conclusion of the hand, whereupon the dealer must turn over those cards for all players at the table to see. The only exception would be if the cards in question have already been mixed in with the muck pile.
 
The rule is straightforward enough when the card-flashing occurs at the end of the hand. But when a player shows his cards to a neighboring player during the hand—particularly if it’s in the middle of a betting round when there are players yet to act—then things can get really messy. Here’s where the interpretation and enforcement of the rule varies. But for the most part, when a player objects and tries to invoke the “show one, show all” rule in the middle of the action, the offending cards will not be exposed to the rest of the table until the showdown.
 
Barbara Connors is a sucker for classic old movies, science fiction, and the St. Louis Cardinals. Her life’s ambition is to figure out the unusual behavior patterns of that unique breed of humans who call themselves poker players. Contact her at fyreflye222@yahoo.com.