In this article, we will learn about the stack-to-pot ratio (SPR) and how it affects postflop play. We will look at three examples with different SPRs. The Stack-to-Pot Ratio (SPR) is the ratio of the shortest stack in the hand divided by the pot. SPR is calculated for each street.
For example, suppose you are playing a $ 2 / $ 5 cash game in which each player has a $ 500 stack. You raise to $ 15 from the button, and only the big blind calls. As SPR increases, the difficulty of the game increases, and hence the role of the skill. The 15.15 SPR is high enough that there will be a lot of postflop maneuvers in this hypothetical hand.
With SPR 1, [AT] on [T87] is very strong and can be played for all the remaining chips. In contrast, if the SPR were 10, [AT] would be average at best, and it would be a disaster to get everything.
Here's a good rule of thumb for small SPR SPR spots: When one pair / top pair dominates, in large SPR situations it takes two or more to play a big pot and expect to win. With detailed charts for online cash games, real-time cash games and tournaments, you'll be prepared for a winning basic strategy no matter what game you play.
Deep SPR hands are the bread and butter of a strong poker player. These are single raises in cash games and in the early stages of tournaments, where most players will be sitting with 70 big blinds or more.
The following hand is one of many you may be familiar with, played between James Obst and Michael Rouen with 25 players remaining in the 2016 WSOP Main Event. It was one of the most memorable hands of the tournament due to the stunning confluence of the Obst rivers. Our analysis, however, will focus on how SPR affects the play on each street, not the famous Obst River.
Blinds 100K / 200K. Fernando Pons opens UTG up to 450K with K ♦ Q ♦. Rouen then calls with 9 ♣ 8 ♣, Obst calls in the small blind with 7 blind 7 ♦, and Nguyen calls in the big blind with 9 ♥ 6 ♣. Four players flop.
Let's talk about the flop! Obst had a bottom flop, Rouen had a straight flush draw, and Pons, the preflop raiser, had top pair with a good kicker. Pons continues for 625k. Rouen rises to 2.025 m, and Obst reaches the summit with a cold rate of 3.3 m. Nguyen and Pons quickly leave the road, leaving the action behind Rouen. This is an easy challenge for him. His hand is not playing well, like raising against a betting range on a 3 Obst flop, which will contain at best two top pair and at worst a bottom set or a stronger flush draw.
More interesting is Ruan's initial raise. While the game is perfect, it is important to consider the SPR of the turn if he is going to 3-bet, which of course is. Not only can Obst have all of the aforementioned hands, Pons is arguably in possession of all of the sets (especially in a 4-pot pot with a textured board where he is less inclined to check top set) as well as stronger flush draws.
If Obst or Pons decide to make 3 bets, Rouen will have to call, leaving just over 1 SPR per move. This means that if his opponent chooses to jam on a brick turn, Rouen will have to fold and give up substantial equity.
We should avoid high equity fold draws because you don't have enough chances to call the jam. In this case, by betting instead of raising the flop, Rouen could comfortably play every move and river. This is especially true for combo draws such as 9 ♣ 8 ♣, because he will have enough equity on the turn to call a big bet comfortably.
Post-flop situation
Rouen hits his straight flush, leaving Obst to die. The sweat is now 13.265m. Rouen sits 16.2m behind and Obst covers 20.1m behind, giving him an SPR of 1.19. On the other hand, Rouen's decision to make such a small bet has its pros and cons. On the one hand, he gets a value from a top two or a set that his opponent most likely has, and leaves a reasonable SPR on the river. On the other hand, it prevents Obst from calling and drawing on the boat with QJ, and makes it less likely that he will bluff on the river when he has a hand like KT or T9.
Obst is only doing worse! He now has a full house with an SPR of 0.6, which means Rouen always needs to double here. (And if it had been some other tournament, he would certainly have done so). Obst makes an oddly small river bet of 4.7m, but it's easy to see why he's trying to get a guaranteed value from flushes while still trying to avoid being hit if hit. However, when the SPR is so low, this is the only bet size that makes sense. Anything less results in missed cost and an awkward balance.
Medium SPR hands are usually either 3-bet pots, played at about 100 big blinds deep, or in single raises, played at about 30 big blinds deep (for example, those played in the later stages of tournaments). If the SPR was slightly lower - if he was sitting with, say, 8k - then check-raising all-in becomes much more preferable. This is because we will win more than our all-B stack size.
Likewise, if the SPR was slightly larger - for example with a 15K stack - then the call becomes more desirable. Check-raising all-in would be an unnecessarily large overbet, and checking-raising to a smaller size puts us in a bad position if we get stuck.
Villain may have many hands that are betting, some of which will be called a check-raise. We can balance our range by check-raising bluffing hands with one high heart, such as A ♥ 2x.
Doug checks and Villain bets 2.4k. Doug's check raises everything - a size that we should always pick with an SPR of about 2 - and the opponent calls from TT. Hands that see a flop with an SPR below 2.5 are usually in 4 bet pots, played with normal cash game stack sizes (e.g. around 100 big blinds), in 3 bet pots in later stages tournaments or single raises where the big blind is defending with less than 15 big blinds.
Editor's note. If you rarely defend your big blind with less than 15 big blinds, I highly recommend reading our guide “How to deal with with interceptions with a tiny stack. "
Now let's look at a hypothetical example. The blinds are 500 / 1k with a 100 ante. Our hero, James, is in the big blind with 13k. Our opponent is Sean on the button with 68k. In this situation, we can check the all-in raise because the SPR is very low. With a deeper SPR, check-raising with medium-strength top pair is a bad move because we often get called from the best hands and end up in awkward positions with a uselessly bloated pot. With such a low SPR, we can check the move to deny equity to our opponent, whose C-bet range contains many overcard combinations (with a decent amount of equity when called). This puts our opponent in a daunting position, as the decision between calling or folding is often very small.
We can also benefit from hands like 88, 99, weaker Tx hands and draws. Now that we have a valuable hand very often when we check all-in, we need to bluff a lot to balance. There are many flush straights on this board that we can use, like 98th, 65th or flush draw. The important thing to remember here is that as the SPR gets smaller, the range of hands we need to "go" with expands. When we flop a pair with an SPR below 2.5, we often have to either check the raise all-in to protect our capital, or just call.
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