In poker, commitment can be defined as your willingness to get all-in with your current holding on the current board against the current opponent. Basically, the stronger the relative strength of your hand, themoremoneyyouwanttocommittothepot. Thismayseemfairlyobvious,butmanyfull-stacked players struggle with this fundamental concept and wonder why they are often lost after flopping tier 2 hands. The usual culprit is that they simply have too much money behind and are unknowingly creating unprofitable situations for themselves time and time again. The fact is, with a 100 big blind stack, you are seldom committed on the flop with anything less than the nuts. This can lead to all typesofcomplications. It’sveryeasytoputtoomuchmoneyinwiththewrongholdingsandnot enough with the right ones.
As a short stacked player, you do not need the nuts in order to comfortably get all-in on the flop. You will almost always be committed with any tier 2 hand or better. Those of you who have played a significant amount of tournaments will likely understand the concept of commitment rather easily. As the blinds rise, stacks inevitably get shorter and shorter. Hands that you might consider fairly weak while deep stacked suddenly become monsters once you are sitting on a short stack. That A3s looks pretty dang attractive when you are sitting there with 10 big blinds and desperate for a double up. You would never consider sticking all of your chips in pre-flop with a hand that weak early in a tournament, but will happily do so when sitting on a very small stack.
Stack-to-pot ratios, or SPR, refers to the ratio between the effective stack size and the size of the pot on the flop. The book Professional No-Limit Hold’em covers this topic in great detail and is, in my opinion, one of the best poker books ever written. I highly recommend absorbing it, as it covers this and many other related concepts much better than I ever could.
The concept of SPR is based on commitment, meaning that the more of your stack you have invested in a pot, the less strong your hand needs to be in order to profitably get all-in. To figure out your SPR, divide the current pot into the effective stack. For example, if the pot is $5 and you have $28 behind as the effective stack, your SPR is 5.6.
As your stack grows, your commitment level with various holdings go down. Once your stack gets above around 80 big blinds, it gets very difficult to create low SPR situations for yourself on the flop without either opening for a large amount pre-flop or being in a 3-bet pot. Higher SPRs on the flop, say 10+, are usually not conducive to stacking off on the flop with one pair hands, because most opponents won’t commit with a hand worse than that for so much money. So a large amount of the time you raise pre-flop, get called, flop top pair, and get it in with a high SPR, you will be beat.
Nevertheless, for some reason, the majority of players insist on playing a “full” stack of 100 big blinds. And the feeling on the subject seems to almost be universal that if you attempt to buy-in for less than that, you are violating some unwritten law and might as well be branding yourself an outlaw in the poker community. It’s almost as if there are thousands of index fingers waggling at you saying “shame on you.”
But in all seriousness, the truth of the matter is that 100 big blinds is a very awkward stack size to play, as it creates multiple uncomfortable situations every session. I would much rather have 250 big blinds than between 80 and 120. At least you have reasonable implied odds and can leverage your stack on later streets.
As a short stack your decisions are almost always fairly obvious. Holdings that cannot typically get all-in on the flop profitably with 100 big blinds, suddenly become viable to do so with a small stack. Take the following example:
You are playing in a .50/1.00 game and bring it in for your standard min-raise on the button after it folds to you. The small blind calls and the big blind folds. The pot is $5 entering the flop. Here is what your SPR would be with various pre-flop effective stack sizes after min-raising from the button and getting a call from the big blind:
According to game theory, creating an SPR in the range that suits your holdings more often than your opponents is tantamount to profit for you. As outlined in Professional No-Limit Hold’em, against opponents with an average commitment range, you can comfortably stack off on the flop with top pair hands with around 4.5 SPR and over pair hands with around 6 SPR. Against opponents who commit more loosely, those numbers rise to 7 and 10, respectively.
As you can see by the chart above, any stack less than 40 big blinds gets us pretty dang close to where we want to be after a pre-flop open min-raise. And considering most opponents will loosen up on the flop versus a so-called short stack, we can definitely tend to err on the higher side of our SPR when making a decision on whether or not to stack off.
In summary, obtaining a low SPR is another of the many reasons that playing a 30 big blind stack is beneficial. You have a luxury that bigger stacks simply do not have, the ability to stack off profitably with your top pairs and over pairs on the flop nearly every time.