The one glaring difference between Omaha poker and Texas hold'em is that players receive four hole cards in Omaha rather than two. In order to produce a winning hand, a player must you use two cards from his hand, but can only use two cards. Like Texas hold'em, Omaha is a game of community cards with a flop, turn and river, and the betting rounds play the same.
Omaha is most often played in a limit or pot-limit format, and the two most commonly spread variations of the game are Omaha high and Omaha 8-or-better.
In Omaha high, the game is very similar to Texas hold'em with each player vying to win the pot with the best high hand, but in Omaha 8-or-better, the pot is split between the best high hand and the best low hand. That's where the "8-or-better" part comes into play as in order to have a qualifying low hand, one must have five different cards in his or her hand that are ranked eight or lower.
For example, let's say there is a final board reading and Player 1 shows versus Player 2's . In this showdown, Player 1 would win the high half of the pot with trip queens and an ace kicker. Player 1 also has a qualifying low hand with his , but Player 2's makes a better qualifying low hand to win that half of the pot.
In the Omaha 8-or-better case where players share a high hand or low hand, they would divy up that half of the pot accordingly. This is why the term "quartered" often comes into play during games of Omaha 8-or-better. In the above example, if a third player in the hand held , he would split the half portion of the pot with Player 2, meaning they would each get one quarter of the overall pot.
Omaha high is a fast-action poker variation and is one of the favorite poker variations for high-stakes players. Due to the wider range of hands that can be made in Omaha as opposed to Texas hold'em, players of Omaha tend to look to make the nuts much more often than not. Other hands are much more susceptible to losing.
In Texas hold'em, a hand that has made the second, third or fourth nuts is often a very powerful holding, nut in Omaha there is a greater chance your hand is no good and you must proceed with extended caution. Let's take a look of an example of this.
The hero has on a board of . Although this is the second best hand with a jack-high straight, any combination of in your opponent's hand would complete a higher, king-high straight and defeat you. Given that a single opponent holds four cards in Omaha as opposed to two in Texas hold'em, the probability is higher than the villain has the nut straight.
Another example would be holding the on a board of . Yes, you have a set of nines, which would be a pretty holding in Texas hold'em, but there are several hands that could defeat you here and in Omaha, it's much more likely one of your opponents is holding such a hand. First of all, there are two sets higher than yours with a set of kings or a set of queens available. Then, there is a straight possible if a player holds . Furthermore, any two diamonds in an opponent's hand would make a flush.
Due to the nature of so many better hands, an opponent may just be calling your bets with a set of kings or queens as they may fear a straight or flush, so even if you are not facing any immediate aggression, you could still be beat so proceed with caution.
Similarly in Omaha 8-or-better, one must be weary of what the nuts are for both halves of the pot and also cautious of players sharing the same hand.
Just like in hold'em, position is an important element in Omaha. Many consider it to be even more important when taking into account all the possible combinations a player can make with an Omaha hand. When sitting in position, you can follow the actions of your opponents and make your decisions based on the information you received. When out of position, it is much harder to make the correct decisions because you are dealing with incomplete information more often.
Another benefit of being in position is that you have a better chance of controlling the size of the pot, which is often based on the strength of your hand and your overall goal in the pot. Being out of position to one opponent or more gives them the ability to control the pot size and also capitalize on the added information of knowing your actions first.
Because Omaha is so focused on the nuts, it seems like an easy game to bluff. A player can represent a wider range of hands in Omaha, and also open up their game a bit more with many more semi-bluffs available. The more you learn about the game, the easy it will become to pick up on these spots and determine how to proceed against various opponents.
It is in this regard that "blockers" also become much more prevalent in Omaha than in Texas hold'em. Blockers are those cards you hold in your hand that prevent an opponent from making a specific hand. For example, if a board reads and you hold the in your hand but no other spades, you may not have a flush, you you know your opponent cannot make the nut flush. This gives you added power in the hand being able to push your opponent off certain hands as he is guaranteed to not contain the nuts.
Omaha poker is a game of action, but it can also be a game of big swings. Many players first learn Texas hold'em before taking up learning the rules of Omaha. Having a good base of knowledge in Texas hold'em helps a lot when making the transition into Omaha.