Playing an Extremely Short Stack: Part II

One of the most important skills a tournament player can develop is the ability to make the correct play with an extremely short stack. Many of these decisions turn out to be more mathematical than decisions involving deep stacks. In the previous column, we looked at a situation in which you had a very short stack (less than the amount of the raise) in the big blind and saw that you had more equity calling the raise, even though it was from a conservative player, with any hand.

I neglected to discuss what exactly constitutes a short stack. How do you know when you have one? It is relatively common for players to compare their stack to the average stack, and decide that a below average stack is short, and one well below average is very short. In a way this is true. Your stack is short compared to the average, but how does this help your decision making? It really doesn’t. A much more useful way to look at stack size is by comparing your stack to the cost per round (CPR.) This is the total amount of antes and blinds that are required for one orbit of the table. Then divide your chip stack by the CPR. The resulting number tells you how many rounds you can play without going broke if you never play a hand. Dan Harrington in the Harrington on Hold’em tournament poker series, refers to this number as M. In Lee Nelson’s Kill series (Kill Phil, Kill Everyone & Kill Elky), Lee and his co-authors including Taylor Strieb, Elky Grospellier, Blair Rodman, and others refer to it as the CSI, an acronym for Chip Status Indicator. Whatever term you use for it, this number is much useful for strategic purposes than knowing how you stack compares to an average stack.

For example, in the WSOP main event everyone starts with thirty thousand. If you lose half your stack on the first hand, you now have half of an average stack. Should you panic and initiate hyper-aggressive play? Not at all! Blinds are only 50-100. Antes haven’t kicked in yet. The CPR is only 150 and you have 15,000. Your M (CSI) is 100. You have plenty of room to play normal poker. This is not the time to go crazy. I have made day 3 of the 2012 main event, but I only have 43,900. This is less than 40 percent of the average stack held by the players who started on day 1A and day 1B. When we return, the antes will be 200 and the blinds will be 800-1600. CPR will be 4200. This leaves me with an M (CSI) of just over 10. I am entering the short stack zone, but I am still far from having a disastrously short stack. Here is a table that summarizes these ideas:

M (CSI) Situation
10-15 Entering Short Stack Zone
7-9 Somewhat Short
5-6 Very Short
3-4 Very, Very Short
0-2 Extremely Short Stack

In tournament poker the concept of fold equity is very important. Fold equity is the amount of equity you pick up because your opponents will fold when you raise or reraise. For example, in my case, as detailed above, I have a lot of fold equity. If everyone folds to me and I shove for 44,000, there is a good chance everyone will fold and I’ll add about 10 percent to my stack. Even if someone enters the pot with a raise to 4,000, he will be hard pressed to call my reraise to 44,000 without a fairly strong hand. I have a lot of fold equity. If my stack was only 8,000, an M of about 2, I’d have very little fold equity. Someone who raises to 4,000 will automatically call a reraise to 8,000. Even the big blind, who already has 1,600 in the pot, will usually call 6,400 more.

In determining a strategy for short stack situations, your total equity (the amount on average you will have after the hand) is the sum of your fold equity and your chance of beating a caller. If everyone will fold to your all-in raise 30 percent of the time and you will win half the time you are called, then your total equity is 30 percent of your stack, plus the pot, plus 35 percent (half of the 70 percent of the time when you are called) of the new pot which includes twice your stack. An illustration may make this clearer. The pot is 4,000, and you have 10,000. The 30 percent of the time when everyone folds, you will have 14,000. The 35 percent of the time when you are called and win, you will have 24,000. The other 35 percent of the time you will have zero. Your total equity is .30 times 14,000 plus .35 times 24,000. This equals 4,200 plus 8,400 or 12,600. Since you started the hand with 10,000, your shove has increased your equity by 2,600. If everyone will always fold when you shove, then your fold equity would have been 4,000. Fold equity is why short stack shoves are so powerful. The amount you win represents a large percentage increase in your stack size.

I apologize for all the arithmetic in this column, but short stack situations and strategies are often best analyzed mathematically. Deep-stack situations tend to require a mix of psychology, table feel and knowing your opponent. Math becomes secondary. Situations where your opponent makes a huge all-in raise on the river, and you have the second best hand can’t be solved mathematically. You have to decide if he could have the hand that beats you. Would he have played the cards necessary to beat you? If so, could he have played them the way he did? Would he make this raise with a slightly worse hand or as a bluff? Math won’t help much in making this kind of decision. In the next installment of this series, I will cover some more specific short stack situations. Today I just wanted to clarify some of the terminology that describes these situations. ♠

Steve “Zee” Zolotow, aka The Bald Eagle, is a successful games player. He currently devotes most of his time to poker. When escaping from poker, he hangs out in his bars on Avenue A — Nice Guy Eddie’s at Houston and Doc Holliday’s at 9th Street — in New York City.