Stuart Rutter's Poker Strategies - Stack Size

Stack Size in Poker, and how it is even more important than you think...

Example #1

You hold , call a raise from the small blind, and hit a great flop of , which gives you a straight flush draw. You decide to play aggressively with a semi-bluff, to give yourself two chances of winning the pot. What is the best way to do this? Is it

a) Moving all-in straight away, b) Check-raising all-in c) Check raising, and moving all-in on the turn

The answer is of course that it depends completely on the stacks size, and more precisely what the stack sizes are relative to the pot.

Let’s say there is about 2,000 in the pot, and your opponent always has you covered; you would move all-in if you yourself held about 2,000, would check-raise with about 6,000, and would need about 18,000 in order to make the third move- the check-raise and then move all-in. To make these moves in a very different way would be wrong.

The crucial part of timing the action is to make sure that you yourself have the last move, and that you are moving in for the right amount. If the timing leaves you with too little to move all-in with, your opponent will have to call; if you end up with an all-in move for something like three times the pot, you are risking more than you need.

This is the most simple example of an idea that comes up time and again, namely that the correct move in any given situation depends principally on the relative stack sizes. To look at things further, we will introduce something that we will call the stack to pot ratio (SPR). The stack referred to is of course the shorter of your and your opponent’s stacks, as this dictates how deep the betting can go:

The stack to pot ratio (SPR) is simply the size of the shorter stack divided by what is in the pot.

Let’s see it at work in another example:

Example # 2

You hold 10,900 in chips in the big blind, and call an early position 900 raise to   . The flop comes , giving you top pair. You feel that you may well be ahead, but that this is a marginal situation.

The pot stands at 2,000, you anticipate your opponent will bet about 1,500, and decide to play for a check raise to find out where you are. You check raise to 4,000, and your opponent immediately moves all in for your last 6,000. What do you do?

You have landed in a difficult position. It looks like you are probably beaten, by an overpair or a jack with a better kicker, but it is now very difficult to pass, as you are faced with calling 6,000 to win a pot of 22,000.

The situation is a no-winner, and often the player with  will decide that they have the odds to call, despite knowing that they are likely to find themselves behind. On reflection, it is important to realise that the player has effectively check-raised all-in, for the full 10,000 stack on the flop. The pot was only 3,500 when the check raise was made, and so the risk-reward ratio of 10,000 to 3,500 is a poor one.

So, what has gone wrong in this situation? The answer is that there must be something wrong with the stack sizes in play. On the flop, the stack to pot ratio (SPR) was 5 (your 10,000 remaining chips relative to the 2,000 in the pot), and so we have realized this is a very poor SPR for a check raise. This leads us to realise that the perfect SPR for a check raise is either about 3, where you can cleanly check raise all-in, or indeed 7 or more, where you can check-raise and still leave yourself the possibility of getting away from the hand. It is these SPR’s of between about 4 and 6 that we have established are in the danger zone, and very ineffective for this move.

However, to have created this situation on the flop, maybe the first thing to have gone wrong was in fact the call before the flop. On calling with a hand like  and hitting this marginal flop, we were always going to face this awkward situation. This leads us to wonder whether we can use the SPR to decide what types of hands to play before the flop:

SPR before the flop

It is slightly more tricky to work out what your SPR is before the flop, but this is something you will get used to in practice. We are going to define our SPR before the flop based on what the situation will be going to the flop once our chips are in the pot:

This means that our SPR before the flop is

The size of the pot once we have called divided by the size of our stack after the call.

So, in our previous example, our SPR before the flop would be 5, as we are playing 10,000 on the flop in a 2,000 pot. We have established that this is a tricky SPR with which to play a speculative hand like . We would rather have a much shorter stack, so that we can move in on the flop, or a stack large enough to justify calling before the flop in order to try to hit a big hand like a straight or a flush.

If we think about a hand like  in a similar spot, I would argue that an SPR of 5 is a very good situation with which to go to the flop. With any less, we might feel committed to call on many flops where we do not hit. An SPR of about five allows us to get away if we do not hit; if we do hit a pair or better on the flop, we will feel far more confident about our hand than we do with . Our stack size is then ideal, as it means we can potentially gain two bets from our opponent. These two bets will be the check raise on the flop, and either our opponent’s subsequent all-in or a further bet on the turn.

If we increase our SPR to 7 or more with a hand like , the situation becomes increasingly less favorable. Now, we are unlikely to win all our opponent’s chips simply by hitting an ace or queen on the flop. The other factor that goes against us is the implied danger of hitting our hand, and having our opponent hit a bigger hand, like two pair or a set. As our SPR increases, the relative danger of hitting a flop like     and having our opponent turn over a hand like  comes more and more into play.

Categories of hands and SPR

So, the picture we are painting establishes that the favorable SPRs for a hand like    are almost the opposite to those for a hand like   . Let’s examine this further by thinking now about three categories of hands that we may call to see a flop with.

Category 1- the solid hands

For this category of hands, you are really looking to flop top pair with a good kicker. The best SPRs with which to operate are between 4 and 6. Anything lower than 4 gives you little value in the hand, and an SPR of between 7 and 15 puts a dangerous number of chips in play if your flopped pair is the second best hand. A very high SPR is however a good spot if you play your hand carefully, as it allows to space to get away from the hands where you flopped pair is beaten.

Category 2- the speculative hands

As discussed, an SPR of between 4 and 6 is the danger zone for these type of hands. An SPR of between 7 and 10 is best.

Category 3- the hopeful hands

These gambling hands will miss the flop most of the time, but can give you a very strong hand if they do hit. Because of this, you basically want as many chips as possible in play.

However, the highest SPRs (for example if you are considering limping for 50 early in a big tournament with a 10,000 starting stack) are slightly dangerous because the slight risk of a nasty set vs set cold deck situation could have horrible consequences. I speak from experience- I went out of the EPT in Copenhagen after 8 minutes, and in last place, with  on a  board!

The inclusion of the pocket pair hands in these categories may be quite confusing, so I will try to explain.

The biggest pocket pairs ( up to ) you would of course play in any situation. The blockbuster hands like  and  are most favorable with an SPR of between 7 and 10. In this situation, there are a good number of chips in play to be won, but not so many so that the threat of being outdrawn by an inferior hand presents too high a risk.

The smallest pairs ( and below) really are best played in tournament poker to try to hit a set, and otherwise to expect to fold on the flop. Therefore, there are suited to a high SPR to give you good implied odds for calling before the flop. It is only if the SPR becomes extremely high (maybe 30 or above) that the unlikely danger of a set over set situation makes the situation less favorable.

The most difficult pairs to play are therefore ,   and . They are listed along with the speculative hands like  as they favor the same sort of SPR zones. If the flop comes low and you hold an overpair, the danger zone will once again be an SPR of between 4 and 6 as this will commit you for all your chips if you decide to check raise.

These rules may be hard to remember, but the overriding principle is not. In almost every situation in poker, it is always worth thinking about what the relative stack sizes are, as it makes so much difference to what your action should be.

Good luck at the tables, and, most of all, have fun!

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