Baseball fans will recognize "isolation" as a play where the pitcher, catcher, or fielder throws out a player who wanders off a base wither in the middle of a steal, or on a caught fly ball.
Poker players can use the concept in a similar manner. Basically, the idea is that some player is in a pot where he should not be and you want to make him pay for his mistake.
Simply, isolation is an action designed to play head’s up with another player by eliminating competition. This move is a simple form of pick-off. If a player is out of line or he does not defend his territory, the other player attempts to play head’s up to take advantage of his superior cards or skill.
A more sophisticated version is to go after a player who attempts an isolation move and either drops his easy target from the action or steals his prey by acting stronger — sort of a second level isolation move.
The best way to demonstrate how to use a pick-off move is to offer several examples.
The first example is the simple isolation. Player A is known to be a very loose player. Player B is acting two seats after Player A. The player in between the two players is fairly skilled but tight.
When Player A raises in an early position and the middle player folds, player B can raise if he can beat the average hand shown down by Player A. The purpose of the raise is to discourage other players from entering the pot by forcing them to call a double raise, thereby getting head’s up with Player A.
This strategy works well in a tight game, but in a wild game, players tend to want to join in pots with raises instead of folds. Some variations where this move works well is to attack a tilt player, a blind, a player close to all-in, a tight player who might fold with a bad flop or other threat, a player who is stuck, an unknown and new player (for speculation and testing), a player who like draw hands, and so on.
The second example is to go after someone trying to execute the first example. To the first example add Player C, a late action seat. After the first two raises, Player C re-raises.
Since the investment is high, this player needs a bit more quality than Player B and should be able to beat at least two-thirds of the hands Player A usually exhibits.
In flop games, Player C needs two high draw cards over anything showing, a small pair (live) with a higher kicker than any suit in another hand and with one card higher than any up card would be minimum to attempt this play.
Even though these hands are not necessarily the favorite, they have possibilities and are not that much of an underdog. The basis behind the strategy is to introduce an unknown and potentially dangerous opponent into what once was a simple play.
Even if no cards help on future rounds, a strong appearance against a check should carry the pot.
There are four different probabilities for this strategy. Win the pot outright, face Player A or B head’s up, face both A and B in a multi-way pot.
Since winning outright completes the play, the only considerations are the other three outcomes. Player A may or may not have a hand but the odds favor a weak hand. Unless this player shows unusual strength, the strategy is to bet with the best hand and try to draw cheaply with potential.
Player B may have pushed with potential, a small pair or a real hand. Since Player C acts behind Player B’s response, Player B is usually good enough to know when to exit so Player C should only bet in the face of weakness or raise with the best hand.
If both Players A and B stay in, the best Player C can hope for are good cards. Probably, both players have real hands and Player C has bad timing. Player C should fold and cut his losses with anything less than top pair and potential on any subsequent bets.
Chasing second pair or longshot draws because the pot is large is not good poker. This move works very well in pot or no-limit poker because of the size of the third raise, but there are other places where it can be effective. In tournaments, especially at the final table, anyone entering a two-person pot is assumed to have a monster because of the high dollar consequence in terms of prize awards.