In community card poker, a player or hand is said to be counterfeited when a community card does not change the value of his hand, but makes it more likely that an opponent will beat it. This occurs primarily in Omaha hold 'em hi-lo split and sometimes in Texas hold 'em. Counterfeiting also occurs in the Badugi variant of draw poker. // Probably starting about the time of World War II, many modern poker games used Community cards (also called shared cards or window cards), which are cards dealt face up to the center of the table and shared by all players. ... Omaha hold em (or Omaha holdem or simply Omaha) is a community card poker game (often referred to as a flop game) similar to Texas hold em, where each player is dealt four cards and must make his best hand using exactly two of them, plus exactly three of the... Texas hold em involves community cards available to all players (pictured here on the left). ... The best hand in badugi, a four-high badugi. ... Draw poker is any poker variant in which each player is dealt a complete hand before the first betting round, and then develops the hand for later rounds by replacing cards. ...

Omaha hold 'em

The more common occurrence of counterfeiting in Omaha is when a person's best possible low hand, called the "nut low", is counterfeited. As an example, say Alice has A♠ 3♣ J♦ Q♦ while Bob holds A♣ 2♦ 9♦ J♠ and Carol holds 9♥ T♥ K♥ A♥. If the flop comes 6♥ 7♥ 8♥, Carol has a lock on the high hand with her 10-high straight flush, but Alice and Bob are still competing for the low half of the pot. Bob holds an 8-7-6-2-A, ahead of Alice's 8-7-6-3-A. In fact, Bob currently holds the nut low hand; no one can have a better low hand. The flop in poker refers to the dealing of the first three face-up cards to the board, or to those three cards themselves. ... A straight flush is a poker hand such as Q♠ J♠ 10♠ 9♠ 8♠, which contains five cards in sequence, all of the same suit. ...

However, if the turn card is 2♣, Alice and Bob's fortunes have changed. Alice now has the nut-low of 7-6-3-2-A, while Bob must still play the A-2 from his hand for a low of 8-7-6-2-A. The turn card did not make Bob's hand worse, but it did make Alice's hand better.^[1] Bob's only chance at the low pot now is if a 3 comes on the river, counterfeiting Alice's hand and giving both Alice and Bob a 7-6-3-2-A to split the low half of the pot. (If a 3 does come on the river, the nut low hand becomes A-4 to make 6-4-3-2-A.) The turn, or fourth street, in poker is the fourth of five cards dealt to the board, constituting one face-up community cards that each of the players in the game can use to make up their final hand. ...

On the other hand, on a flop of 8-7-6, a hand containing A-2-3-4 is considered counterfeit-proof, because it currently is the nut low (8-7-6-2-A), and even if an A or a 2 arrives on the turn, it will remain the nut low (7-6-3-2-A) and will remain protected from counterfeiting on the river. A player with this type of protection can be bolder in betting.

Texas hold 'em

Counterfeiting in Texas hold 'em is similar to Omaha, in that hands do not change value, but normally Texas hold 'em counterfeiting is less likely to cause a player to lose an entire pot. On a flop of Q-J-T, a player holding A-K will have flopped an ace-high Broadway straight. If the turn card comes a king, the player with A-K will still have the same straight, but now so will a player with A-7, making a tie. The A-K player's hand didn't get worse in rank, but it becomes less likely to win the entire pot. // In poker, players often use slang terms for particular types of hands. ...

Counterfeiting in Texas hold 'em more often leads to ties, like in the example above, but in some cases it will lead to losses. For example, if the flop is J-T-9, and the turn a queen, a player who held K-Q will be counterfeited and able to lose to a player with A-K. Likewise, if the flop is J-7-5, a player who has 7-5 would have two pair and be ahead of a player with pocket aces. If another jack comes up, however, the first player's hand gets objectively stronger -- from 7s and 5s to Js and 7s -- but now is losing to the second player's As and Js, as the original pair of 5s was counterfeited by the pair on the board.

Badugi

If a player holds a hand such as A244 (all different suits), the hand value is really A24 as a player can only use one of the cards that is paired. This is known as a three-card hand. Similarly a hand such as A222 would only hold a final value of A2, a two-card hand, as the other 2 cards are counterfeited. A three-card hand beats any 2-card hand.^[2]

Notes

1. ^ Counterfeit definition
2. ^ Badugi hand values