An Omaha Tutorial
For those new to the game of Omaha, or those who might need a refresher, here's a tutorial of the game courtesy of PokerNews' Rules Section.
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 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.