High/Low is variant of Omaha where you can qualify for half the pot if you have a 'low'. It's played in a similar manner to Pot Limit Omaha, but with a few key differences. Omaha High/Low is a staple game in the big mixed-games in Las Vegas, and learning it is essential if you want to become a good all-round poker player.
Omaha High/Low is structured just like Pot Limit Omaha (Omaha Hi) or Texas Hold'em--with a dealer button, a small blind and a big blind. These blinds rotate one position clockwise after each hand, ensuring that all players are affected by them equally over the course of the game.
Unlike Pot Limit Omaha, where players can bet up to the size of the pot whenever they want, Omaha High/Low is nearly always played as a limit game - where the size of bet is fixed. Omaha is split into two sizes of bet - big bets and small bets, with big bets typically twice the size of small ones. Pre flop and on the flop players can only make small bets, and on the turn and river they can only make big bets.
As a basic example, in a €2/€4 limit Omaha High/Low game the big blind would be €2, the small blind would be €1, and during the betting intervals pre-flop and on the flop you can bet or raise €2, and during the betting intervals on the turn and river you can only bet or raise €4.
In order to qualify for a low hand, a player has to have five unique cards under eight. If you have the best low hand you are entitled to half of the pot at showdown. If there is no low hand possible, the hand can only be contested by the high hand. If you have both a good low and a good high hand you can win the entire pot, a practice commonly called 'scooping'. If you share an identical low to another player's, you both have to split the low half of the pot, a practice commonly referred to as 'quartering' (because you only win a quarter of the pot if you have no high).
Omaha High/Low is growing immensely in popularity at the moment, and with good reason. It's a game that's always full of action because numerous players often chase one or the other half of the pot. Although usually played in a limit format, Omaha High/Low produces much larger pots on the whole than any other limit game, and is an intricate and extremely interesting game once you start to get used to its nuances.