Short Stack Poker Strategy

For many players who regularly sit down at cash tables in the modern game, once they have found some level of comfort with the quality of their 'full stacked 100bb' skills, one of the ways in which they frequently find themselves in awkward situations is when faced with an opponent wielding a stack typically sized between 20 – 50 big blinds. Here I hope to shed some light on short stack poker strategy to help improving players who are looking for some answers on the matter.

The good news is that once we find ourselves in a situation where the money is often going in preflop, we can use some simple mathematics to make quality decisions. We are also happy to hear that the vast majority of short stackers are players who started their session with a full or close to full stack, but haven't re-bought. This is an indication that the player isn't following any particular strategy related to stack size, which any competent player will do.

This information, along with our HUD stats should allow us to nail down exactly what strategy to use against them. No more guessing, or even better, no more nitting it up. Many players fall into the trap of folding too much against a short stacked opponent for reasons such as having a fear of getting shoved on and not knowing how wide they can profitably call. They just have a feeling that they don't want to get involved, assuming that it isn't so important anyway. 

I'll start with some general principles and adjustments we need to make. As the effective stack size decreases our implied odds also decrease. This affects the range of starting hands we should be opening pre flop and also our cold calling range.

The shorter the stack the more extreme your adjustment should be. Rather than posting a number of hand charts for each stack size, I will attempt to give more general advice so you can think for yourself in-game, and do your own EV calculations to make yourself more comfortable.

For our purposes we should distinguish the starting hands between high equity type, and low equity type/speculative. 

Hands such as KK and AKs are high equity hands, they will often be the best hand on the flop, and will win an all-in confrontation with a high frequency. With high cards you will simply get to showdown with the best hand a lot more frequently than low cards. 

Hands such as 54s and 86s are speculative hands which will not be ahead on so many flops when multiple players hit, but when they do hit you have a chance to flop or later make a strong '5 card hand'. This hand type needs to be playing against a deep stack to maximise its profitability. Even in today's tougher games I still see players cold calling this hand type when a short stacked player has open raised, thinking they can use their post flop skill advantage to make it a profitable move.

One adjustment we can make with this hand type is to 3 bet them in position when a full stacked opponent opens and we have short stacker to our left. This way we side step the increased probability of getting 3 bet if we cold call and having to fold, but at the same time we have a hand which can flop well, even if traditionally small suited connectors aren't at their best playing a pot with a small stack to pot ratio. Here we are also utilising our fold equity pre flop which may even work out to be more profitable than cold calling without any short stackers present.

Pocket pairs and suited aces are a special case, somewhere in between high equity and speculative. For example, if a 25bb stack opens from the small blind and we have 22 in the big blind, we should no longer be looking to flat call hoping to hit a set. We just won't win enough chips even if we can get the small blind to put all of his chips in the middle to make it a profitable plan of action.

However, one thing that pocket pairs are okay at, is bluffing in an all in situation where we are sure we have at least some fold equity, and even if we get called we can reasonably expect to have around 35% equity. Suited aces will have slightly less equity if called, but can be used to extend your bluffing range if your opponent is expected to fold with a high enough frequency.

When we do find ourselves playing multi-way with a mix of short and deep stacks we just need to accept that our creative play options against the other deep stacks are almost non existent. Fortunately, in the micro stake games we have an added bonus that many players will adjust terribly against the short stack and sometimes we will have a strong hand, this more than makes up for when we have to miss out on potential value to avoid a short stack exploiting us. 

In a way, the need to to play more straight forward, makes our life easier, we get to play a value orientated strategy which gives us less to think about, and less scope for errors which will reduce our win rate.

Over recent years the average open raise size has reduced from all positions on average, but one spot where we should be as small as possible is from late position with a short stacker still to act. I recommend 2.4bb from the CO and small blind, and a min raise from the button.

This means we lose less when we get re-raised pre flop, and we also make the pot smaller to begin with, making it a less attractive steal opportunity. Most short stackers at the micro stakes play a strategy which is too rigid, meaning that when we use a smaller size to steal with, they are unlikely to adjust enough to counter.

It should now be obvious that one of the benefits of playing with a short stack, is that we can steal in many situations. Even bad players learn quickly that they can get many folds in a variety of situations. One of the most common spots is when there is an open raise preflop and one or more callers. The average short stacker will be shoving all-in with a wide range and expecting to get plenty of folds.

So it logically follows if we have a premium hand it is worth considering cold calling instead of the usual squeeze play, and hoping that the short stacker shoves. Not only has under representing our hand helped us to trap one player for all their chips, the original raiser might now feel they can get us to fold by shoving the remainder of their 100bb stack. 

There are many different types of useful EV calculations we can do to work towards perfecting our anti-shortstack play. Here is probably the most simple, a method to work out what range of hands we can 3 bet shove all-in against a short stacker.

In our example an unknown 30bb stack open raises to x3bb from the cut-off in a 9 handed micro stakes cash game. The button and small blind both fold

Our hand is ATs and we are in the big blind

First we need to make an assumption about what range of hands villain will call with if we shove. It doesn't matter if you consider this range accurate, the mathematical method is what's important here.

So lets assume villain is opening 25% of hands and will call with 22+, A2s+, K9s+, Q9s+, J9s+, T8s+, 97s+, 86s+, 76s, 65s, 54s, ATo+, KTo+, QTo+, JTo, T9o. This works out to about 50% of his original opening range.

ATs vs this calling range has 36.24%, leaving villain with 63.76%

Part 1 – What happens when all the chips go to the middle.

Using the standard EV formula

EV = [Probability(Win) * what we win] – [Probability(Lose) * what we lose]

EV = [0.4222 * (1.5bb(the blinds) + 3bb(villains open raise) + 27bb(the rest of villains stack))] - 

          [0.5778 * (30bb] 

       = 13.229 – 17.334 = -(4.03bb)

So when we do get called we can expect to lose on average a little more than 4bb

Part 2 – What happens when we take into account fold equity

FE = 50%

Using the same formula as above

EV = [0.5 * 4.5bb] – [0.5 * 4.03bb]

   

      = 2.25bb – 2.015bb

       =0.235bb

Now with fold equity taken into account we now have a slightly profitable shove, although I haven't mentioned rake yet which won't change things too much but still shouldn't be ignored entirely when looking at close decisions.