How to Isolate a Short Stack

Isolating a short stack is the act of raising or shoving over a short stacks open-shove. This is an important tactic to know and understand, as you will be using it to try to build stacks. It's not always easy to do though. You will need to consider many variables including ranges, pot odds and table dynamics. One variable might be in your favor while the others aren't. This can make your decision to isolate a short stack a difficult one.

Opponent's Shoving Range

The most important variable you need to consider is your opponent's shoving range. You will need to put them on a range of hands so that you can determine that either your hand has more equity verses his range or that you're getting a good enough price to justify having less. This will be different from player to player. One player might shove 15% from middle position with 10 big blinds and another player might shove 25%. Putting an opponent on a range is one of the most difficult aspects of isolating short stacks.

One way I try to determine my opponent's range is to assume they have the same range as I do. While this isn't accurate, it's not going to be so far off (in most cases) that I'm making a horrible play. This will work until you have had more time with this opponent to get a better idea as to what his range is.

Another way to figure out your opponent's range is to determine if he is a regular or random. Regular players generally have a better understanding of the push/fold game. So you can expect them to shove much wider than a random. If you don't know if the short stack is a reg or not, a quick look on SharkScope should tell you.

Position will also be a good indicator of how wide someone is. As a rule of thumb, shoves are going to be much wider near the button than from under the gun. A player from under the gun will have a tighter shoving range because there are more players to act after him.

Pot Odds

Once you have determined your opponents range, you'll want to figure out how much equity your hand has verses it. You won't have the time to figure this out with Poker Stovewhile you're playing, especially if you're multi tabling. This will be something you'll want to work on when you review your hand histories after you're done with your session.

I have found it to be easier for me in game if I memorize certain pot odd percentages. For example, I have memorized that pot odds of 2 to 1 is 33%, 1.5 to 1 is 40% and 1 to 1 is 50%. Memorizing these three will help you figure out your percentage quicker when you are getting an odd number like 1.8 to 1. It's between 1.5 to 1 and 2 to 1, so you can make an educated guess that it's about 36%. Converting your odds to a percentage will make it easier to figure out whether your call is +CEV or not since the hand equities you're working with are in percentages -- you'll just compare the two.

Example Hand

For example, say you have A7s on the button. The blinds are 75/150 and you have 2,200 chips. It folds to the player in the hijack who shoves for 8 big blinds, making the pot 1,425. You figure his hijack range to be pretty wide here, about 30%. Verses this range, we know that A7s is about 50%. Since we need to call 1,200 to win 1,425, our odds are 1.2 to 1 or 45%. This is good enough to make the call as we have a +5% margin.

Remember that for a call to be +CEV, your equity must be better (higher percentage) than the pot odds you're getting. In the example above, 50% is higher than 45%, so a call would be fine. If our equity were lower, say 40%, it would be a -CEV call.

Other Variables to Consider Before Isolating a Short Stack

Now, just because you're getting a good enough price to isolate a short stack, it doesn't mean that you should. Other variables should be considered.

For one thing, you need to determine whether it's worth the risk or not. Are you desperate for chips or can you wait? You don't want to race and push a small 5% edge if you don't have to. You might lose a large fraction of your stack if you don't win the race.

You should also determine if your equity in the tournament is going to increase by much. If you have 10% of the chips in play, you have plenty of equity in the tournament. Picking up a short stack won't increase that by much, if at all. Remember that the more chips you have, the less each chip (you don't have) is worth. So, you could theoretically stand to gain more by passing on a spot than taking it and risk losing.

Something else to consider is the table dynamics. If you isolate this short stack and win, will you have the chip lead on the bubble? Even if you're not getting the correct pot odds, that could still be worth taking the risk for. Would isolating a player give you a deeper stack than the guy to your immediate left? That might be worth isolating a player over. These are only a couple of the variables or factors that you should take into consideration. Sometimes they'll be the deciding factors, regardless of your opponent's range or the pot odds you're getting.