The Importance of Stack Sizes - Stack Size Poker Strategy | Poker Strategy

The effective stack size is something you always need to be aware of and need to take it into consideration with every decision you make in No limit or Pot Limit Hold'em.

Lets say you have (K-Diamonds)

in the small blind and open from this position. The big blind calls you and you see a flop heads-up. The flop shows (10-Clubs)

. Nice flop, but what are you going to do? You decide you want to get a lot of money into the pot and you start thinking about your optionss, such as continuation betting, check-raising on the flop and check-calling the flop to then check-raise the turn. These are quite a few options, and we haven't even thought about the bet sizes yet. Do you want to go all-in on the flop, or are doing this on the turn, regardless of whether you hit or not. What do you do?

Logic answer: It depends. For one, it depends on the effective stack sizes and the relation between the stack sizes and the size of the pot. In the course of this article we will go into more detail on this. Taking stack sizes into account is of great importance in both No Limit and Pot Limit Hold'em variations. In this article we will be focussing on No Limit and we will be looking at some example hands that were taken from tournaments, but the lessons learned from them can also be applied to cash games, Pot Limit Hold'em and even Pot Limit Omaha.

In the mentioned example you could choose different options depending on your stack size. Lets say the effective stack size (the size of the smallest stack) is $10,000 and the pot is already $10,000, then you can decide to go all-in immediately. If the effective stack is $30,000, then you can choose to check-raise your opponent, and if the effective stack is $50,000, then you check-call him on the flop and check-raise him all-in on the turn.

What is crucial here is that you want to create fold equity and you want to maintain control of the pot. If you go all-in and your opponent only has a small amount to call, then you have very little to no fold equity. If you go all-in and your opponent has to call a very large amount, then you are taking too big a risk, because you are likely to only get called by hands that have you beat. At the end of the day you only have K-high at the moment, so don't take more risk than necessary.

Stack-to-pot ratio
This principle is worked out further in the concept of stack-to-pot- ratio (SPR). SPR is a ratio that was introduced in the book Professional No Limit Hold'em: Volume 1 by Ed Miller et al.

SPR is the effective stack size (the size of the smallest stack), divided by the size of the pot. If you have a stack of $12,000 and your opponent has a stack of $9,000 and there is $1,000 in the pot, then the SPR is $9,000/$1,000 = 9. We are using the effective stack size for this calculation because that is the maximum amount you can win or lose.

The second example is as follows: You have $15,000 in Chips in the small blind and get (8-Clubs)

. You call a $1,200 bet form a player in middle position, who has a larger stack than yours. Before the flop, the pot is $3,600, including antes and the money from the blinds. The flop is (7-Hearts)

and you check. Your opponent now bets out $2,500 and you decide to raise to $6,500, after which your opponent goes all-in. You still need to call $7,300 to win a pot of $24,100

This is, in fact, an easy call, as you only have to call a small amount in relation to the size of the pot. On the other hand, you won't be ahead here very often. If you're lucky you might be up against a smaller pair or AK, but more often then that you will be up against a higher pair. By check-raising here you are basically putting your entire stack on the line. Before you check-raise the pot is $6,100 and you are risking $14,000 to win that. This is a bad situation to find yourself in with an average hand and risking your tourney life. It seems like you didn't pay a lot of attention to the effective stack sizes.

On the flop your SPR is almost 4 ($14,000/$3,600). You can't really fold your hand anymore after you check-raise, and to check-raise him all-in straight away would mean to make an overbet, and you can be sure that no weaker hands will call you. You would be raising from $2,500 to $14,000, which is a relatively large overbet. This doesn't seem like an ideal situation. It would be much better if you could check-raise all-in with a smaller SPR, say 2.5 – 3, or if you could still fold after you check-raise (not considering whether check-raising here is even a good play in the first place). In order to be able to fold after check-raising, you need an SPR of at least 7 or higher.

The problem started with the call preflop. With hands like 88 you often play for setvalue, and if you get the money in without improving your hand, the chance is high that you will be up against a better hand and sometimes have a coinflip situation against a good draw. SPR can also be seen as the degree to which you are committed when playing a pot. With a very low SPR you are almost directly committed and the higher the SPR, the less committed you are.

SPR preflop in No Limit Hold'em
Your SPR before the flop is the size of the pot after we call, divided by our stack size after the call. In our last example we had a relatively speculative hand with (8-Clubs)

, and a hand like this is difficult to play with an SPR of 4 or 5. These kinds of hands play much better when you have an SPR of about 7, where you still have some leeway to draw or make your opponent fold a better hand by being aggressive.

Hereby, you can classify your hands preflop and decide with which hands you want to see a flop. The first category includes the good hands with which you can hit a nice top pair, such as AQ, AKo and even AJ and KQ. These hands do pretty well with an SPR between 4 and 6. You want to flop a good pair with a good kicker. If your SPR is much higher and you are getting a lot of action, then these 1-pair hands are often not good enough to take down the pot with. You need to make sure to not just blindly toss your chips away with simply top pair. If your SPR is high you will want to take it easy on with this hand because the implied odds of weaker, speculative hands will increase when SPR is high.

The second category flops a relatively good top pair with a relatively good kicker. Hands like QJs, KJs, JTs, TT, 99 and 88 belong in this category. With hands like these you don't want an SPR between 4 and 6 but preferably higher. If you encounter a lot of resistance you still want to be able to fold your hand and possibly go all-in with some fold equity if you flop a strong draw, for example. Therefore you want an SPR between 7 and 10.

The third category includes real drawing hands or hands with which you want to hit a set. These hands are therefore low suited connectors and low pocket pairs up to 6's and 7's. These hands are best played with an SPR between 10 and 20. If the SPR is much higher then that you will have a situation in which you will often need the nuts in order to get all your chips into the middle, as your set of 2's will often not be good anymore.

Hands we haven't mentioned yet are the absolute monsters like Aces and Kings. These hands often play themselves, but play best with an SPR between 6 and 10. Then there are enough chips in play to get good value out of these hands.

In the book Professional No Limit Hold'em, the authors go into more detail about manipulating the size of raises preflop in order to create a good SPR for your hand on the flop. If, for example, you are playing (Q-Hearts)

, then a good SPR would be between 7 and 10. Lets say your are aiming for an SPR of 8, then you should make an appropriate raise preflop to reach this SPR. If you have (A-Hearts)

, then you should aim for an SPR between 4 and 6. This makes sure that you can play your hand comfortably after the flop. The one thing the authors of the book don't take into account is that other players can easily figure out your hand ranges, as a result of which you would become very predictable.

I would strongly recommend that you read the book Professional No Limit Hold'em. Even aside from the SPR concept it is just a really good poker book.