The isolation raise is a preflop bet that takes place when a player raises after someone has limped in before them. The idea behind this bet is to force the pot into a head-up situation against the player who limped in by raising a large enough amount to force other players out of the betting. The reasoning behind this play covers quite a lot of territory. Firstly is the fact that weaker players are the ones who usually limp into a pot instead of raising, so getting into heads-up play against them can be very profitable. On top of that, the player that limps is almost always going to call the isolation raise and end up playing poorly on the flop, turn and river. You get extra money without much effort when they call the bet that you made and end up folding after the flop.
The quality of your hand is very important to making a good isolation bet. You want to look for a hand that will stand up more strongly in heads-up play. While you can safely take AA or KK to the flop and beyond, hands like AJ or KQ work much better when you’re just worrying about one opponent. If you’re in position, however, you can definitely look for connectors and suited cards with some value, such as 9T or AT suited.
How much should you raise? A good rule of thumb when you are in position is to up the action by four big blinds, plus one for each limper. When you’re out of position, add one extra big blind to your bet. Let’s say that you have two players limping in before you, and you’re in the small blind while holding AK. In this case, you should raise to six blinds. If you were on the button, you can get by with raising by just five big blinds.
As you can imagine, an isolation bet is a rather tricky play that can end up backfiring on you if you haven’t been paying attention to your opponents. There are players who limp in with big hands like Aces to get more money in the pot, for example. Make sure that you’re paying attention to someone’s betting patterns. If you see someone who’s normally aggressive limping in, then you have to consider the fact that they likely have a large hand.
Knowing about isolation betting can help your defensive game as well as your offensive one. Better poker players are going to be the ones using this play. If you’ve been tangling with someone for a while and they suddenly raise in the manner we’ve described, you can put them on a hand, as well as a strategy. The better player is going to be trying to get the pot heads up, just like you. Try to restrict use of the same strategy against them, unless you feel like your hand is that much better than what they’re likely holding.