Omaha is a variant of Texas Hold'em Poker. Omaha is considered, by some, to be the hardest game of Poker to master. Of all of the different games of Poker, Omaha is for many the hardest to learn to play and the hardest to bluff in. It is played most often at fixed limits, like Texas Hold'em and pot limit.
The play of Omaha is very similar to the play of Texas Hold'em and other Poker games, but different because you cannot use all of your cards.
How to Play
The dealer will deal each player four cards, starting to his left. Once all players receive their cards a round of betting occurs. Omaha is rarely played no-limit, meaning you can at any time bet any amount. It is generally a limit or pot-limit game. The betting starts to the left of the Big Blind. The Big Blind and the small blind are just left of the dealer. The small blind, who is one left of the dealer, has to put half of his "blind" or payment for seeing your cards into the pot before he can see his cards. It is a forced bet. The Big Blind, who is two left of the dealer, pays the entire "blind" before he can see his cards. This, too, is a forced bet. Once cards are dealt the player left of the Big Blind can call the blind, bet, or fold. Betting rotates around the table until it reaches the Big Blind who can call any subsequent bets, make a bet himself, or check, meaning that if nobody has bet, play will go to the flop for free.
Once the first round of betting is over, here comes the flop. The top card of the deck is "burnt" or discarded, never to be seen or played. Then the dealer takes three cards for everyone to see. These are "community" cards. Community cards can be used by all players to create a five card hand along with your "hole cards" or the cards dealt to you by the dealer at the start of the hand. The catch for Omaha, however, is that unlike Hold 'Em, you cannot use all of your cards or just one of your cards in your hand. You must use exactly two cards from your hand and three from the board. In Hold'Em you can use one from your hand and four from the board or if your hand is particularly unworthy, all cards on the board! So, once the flop is dealt, another round of betting occurs, this time starting directly left of the dealer. The players can once again "check, bet, or fold or raise" to another's bet. Once this round of betting is complete, comes the turn card.
Prior to the turn card another card is "burnt" or discarded. Then the turn card is put next to the flop. This is another community card that all players can use in making their five-card hands. Do not make the mistake of thinking you can use four of the cards on the board and one in your hand, or any other number than three on the board and two in your hand. Again, when the turn is dealt, a round of betting occurs starting left of the dealer. Once this round of betting is complete, comes the "River" card.
Once the round of betting for the turn is complete one card from the top of the deck is "burnt" and the river card is shown on the board. This is another community card, and once again a round of betting occurs. After this round of betting is complete hands are shown and the player with the best five-card hand wins. Hand rankings are the same as hand rankings in Texas Hold'Em and other Poker games.
Omaha is a dynamic game in which the strength of ones hand (and that of your opponents) may dramatically change during the hand. It is important to realise what the nuts is and make sure you have it or close to it before investing large numbers of chips. For example in a 5 way pot on a board with 3 to a flush, it would almost always be a mistake to call a bet relying a straight or 3 of a kind to hold up. Similarly on a paired board it would be a mistake to invest too many chips with merely a flush or straight.
For this reason it is important not to slow play your hands in Omaha, as you will be drawn out on with a much higher frequency than in Hold'em. It is better to play aggressively and quickly with your best straights and flushes because if the board pairs they can become practically worthless.
Probability derivations can be calculated.