Exploiting Profiles:
Episode I – The Calling Station

Player profiles are a powerful new feature that enables us to explore exploits against an entire suite of player tendencies rather than a single imbalance at a single node, as nodelocking does. By combining profiles with custom reports, we can test conventional wisdom about how to exploit common player types and discover more profitable heuristics.

In this article, we will derive some heuristics for exploiting calling stations specifically. Before we proceed, however, it is important to understand what exactly player profiles are and what they can and cannot do.

The Limitations of Player Profiles

Broadly Applied

The label “calling station” probably conjures some images or assumptions in your head. The player profile “Calling Station” certainly aims to model those assumptions, but these profiles are blunt tools. They work by assigning a player extra incentives to take certain actions. In the case of the calling station, the algorithm gives them more (extra) incentive to check or call and less incentive to bet or raise.

These incentives are applied at all postflop decision points, regardless of any other factors. So, while real humans might be more likely to bet one type of hand (an overpair, for example) but more likely to check a different one (such as a draw), the profiles prefer betting or checking all types of hands to exactly the same degree.

Not Forward-Looking

Player profiles are not forward-looking. That means, when we calculate the optimal turn strategy against a player who will call the turn too often, we do not make any assumptions about how they will play the river. Only after we bet the turn, they call, a river card is dealt, and it’s time to calculate the optimal river strategy, do we introduce the assumption that the opponent will call too often.

Throughout this article, I will use “Calling Station” with capital letters to refer to the player profile and “calling station” with lowercase letters to refer to the human players who embody these traits. This will serve as a reminder that the profile does not perfectly map real human behavior.

The Experiment

We will begin by generating two custom reports for the purpose of comparing how flop c-betting strategies in a UTG vs BTN 100bb SRP differ when BTN is a Calling Station versus when they are a GTO opponent.
Then, we will compare specific turn and river scenarios to see how these strategies play out on later streets.

As with any custom postflop solution, it’s up to us to choose the preflop starting ranges. For our purposes, we will prefill the Hero’s (UTG) range with the GTO strategy for the configuration and make only slight adjustments to the Calling Station’s (BTN) range. All mixed strategies will be purified by rounding them in favor of call over raise or fold. This will result in less dramatic adjustments than the postflop weighting, but it also eliminates reliance on strong assumptions about how a human player would handle preflop decisions.

OOP C-Betting

Custom aggregated report: UTG c-bet flop strategy vs BTN GTO

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vs BTN Calling Station

Does it surprise you that we bet more often into an opponent who calls too much, even when we’re out of position?

There are two factors at play here:

The Calling Station’s overly weak preflop calling range causes us to flop more of an equity advantage, on average. This gives us more incentive to bet, as they will more often find themselves holding a bad hand. They can either fold that equity immediately or call and carry a weak range forward to the turn. Either outcome is fine with us, because…
Even without making any assumptions about how the Calling Station will play the turn (which, remember, are not built into the flop strategy), they will start at a disadvantage because of their overly weak range, just as they did on the flop. When we bet again, as we often will, they will face the same dilemma: forfeit their equity or play the river with a weak range. Another way of saying this is that, because their weak calls will have poor equity and poor equity realization, we don’t mind them all that much, even when we are betting somewhat weak hands ourselves.

For example, one of our lowest-equity continuation bets on Q♣6♦2♠ is T♠8♠. The Calling Station’s weakest call is 9♠7♠. Not only are we ahead of that, but we will also play pretty well against their second pair, third pair, and small pocket pair holdings, which may pay off our value bets or fold to our bluffs on future streets.

Bet Sizing

It’s worth noting that our bets are mostly small, almost exclusively 40% pot or less. This undermines the myth that the best way to beat a calling station is to wait for monster hands and then bet huge.

Waiting for monster hands and then betting huge is one way to beat calling stations, but it is not the most profitable way.

That is one way to beat them, but it is not the best or most profitable way. Against a calling station, there are many spots where you will be favored even when your hand is not especially strong. And even most calling stations understand they should fold more often to large bets than to small ones. So you miss out on a lot of opportunities by waiting for a (nearly) sure thing, and you won’t even necessarily maximize your winnings with your monster hands by playing them this way. Smaller bets on early streets keep their range extra-wide, generating more value from the bottom of their range before you drop the hammer.

The exceptions to the small-bet rule occur on low paired boards and a few other flops where UTG has an especially pronounced nuts advantage.

Barreling the Turn

QJ5r is a good example of a flop where UTG c-bets more often into a Calling Station than into a GTO opponent. When restricted to a quarter-pot bet, UTG bets 83% of their range into the Calling Station, as opposed to 71% into the GTO opponent. When permitted a second, 40% pot bet size, UTG makes heavy use of this against the Calling Station as well, but for the sake of comparison, we will restrict them to quarter-pot, which is the most commonly used size against the GTO opponent.

We have seen that, on the flop, UTG often bets into a Calling Station at a higher frequency than they would a GTO opponent. However, if BTN calls quarter-pot on Q♥J♦5♣, UTG barrels a 2♠ turn more often into the GTO opponent than into the Calling Station, and their average bet is larger.

Why do you think this reversal in the preference for aggression happens?

UTG barrel turn strategy on QJ52r vs BTN Calling Station

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vs BTN GTO

Don’t worry if you had trouble figuring this out (I did too)! What ultimately clued me in was comparing the UTG’s range constructions.

*UTG sometimes uses a larger (more polarizing) bet size vs. the GTO opponent, but for the sake of simplicity, I’ve lumped both bet sizes together. The trends are easier to see this way.

The most apparent difference is that UTG’s range contains many more high-equity hands against the Calling Station.

Against the GTO opponent, there are two types of hands UTG bets substantially more often: pure bluffs, and their thinnest value.

Bluffs

The reason for betting more bluffs on the turn against a GTO player is the most obvious: A calling station folds less often, and with just one street remaining to play, semi-bluffs have less equity and less hope of bluffing BTN out later. Also, because UTG has more (thin) value bets against GTO, they are incentivized to bet more bluffs as well.

Thin Value

The thin value is more confusing. Shouldn’t we be able to get thinner value against the Calling Station?

The hands in this bucket are mostly second pair (Jack-x). If they bet and get called, they have a tough time playing the river. The thing is, they also have a tough time if they check and face a bet. When playing from out of position, you have less control of the pot, and it is generally correct to make thinner value bets because checking OOP does not guarantee you see the river.

However, because the Calling Station bets less often, UTG is more likely to see the river for free when they check their AJ. So, they have less incentive to choose the “lesser evil” option as they sometimes would at equilibrium.

And this leads to the answer to our question: UTG bets less often against a Calling Station because it expects to face far fewer bets, so many mediocre hands prefer to check for a greater chance of realizing.

Tripling the River

If UTG bets 67% pot on the 2♠ turn (to avoid introducing range splitting as a confounding variable, I eliminated the option to bet 196% pot, which was only used at equilibrium) and gets a 7♦ river, they now bet again at a higher frequency into the Calling Station than into the GTO opponent. Perhaps that’s what you’d expect, even though it’s not what we saw on the turn.

But there are some other interesting trends here as well. How would you describe the shape of each betting range?

UTG barrel river strategy Q♥J♦5♣ 2♠ 7♦ vs BTN Calling Station

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vs BTN GTO

The top half of UTG’s range plays four fairly distinct strategies against the GTO opponent:

With QQ, they heavily block BTN’s range for calling a large bet, so they bet small as a trap.
The rest of their strong hands—everything stronger than AQ—overbets.
With AQ, of which they have many combos, they mostly check with the plan to call a bet.
The rest of their Queen-x block bets (to mostly fold vs. a shove).

Against the GTO opponent, UTG mostly bets either 25% pot or 150% pot, making only scant use of the bet sizes in between.

Against the Calling Station, the medium bets of 100% and 40% pot are the most commonly used. UTG has some block bets, but they never overbet. This might be a more surprising conclusion, as we would expect UTG to make more ambitious value bets against a Calling Station.

UTG does in fact make more ambitious value bets, even if they don’t use the overbet size. Let’s revisit those four strategies we identified against the GTO opponent. When betting into the Calling Station…

With QQ, they sometimes block and sometimes bet larger. This exploits the Calling Station’s looseness but also their passivity, as they do not raise the block bet as often as a GTO player would.
Other hands stronger than AQ mostly check or bet full-pot but rarely overbet.
AQ mostly bets 40% pot rather than checking. As with QQ, this slant towards aggression exploits both the Calling Station’s too-loose-and-passive tendencies.
Weaker Queen-x block bets, but AJ frequently block bets as well, and even a bit of KJ sneaks into the range. As we have discussed, lowering the threshold for value is one of the most important exploits against a Calling Station.

Still, the mystery remains: Why does UTG make smaller value bets with hands like JJ and AA against the Calling Station than they would against the GTO opponent? The answer lies in how the Calling Station plays on the previous streets. It slow-plays strong hands much more often and as a result reaches the river with far more high-equity hands like JJ and QJ, than the GTO player would. This is a very important lesson to remember when developing strategies against calling stations. Even though they tend to call too much, you must be careful not to “value-own” yourself, as they can frequently arrive at the river with strong hands you wouldn’t expect (because of the passive line that was taken).

Bluffing

It’s time to dispel another myth, which is that you should never bluff a calling station.

In fact, because of their loose calls on earlier streets, the Calling Station reaches the river with disproportionately many weak draws and pairs. Even allowing for the fact that BTN will get a little too sticky, UTG still pure bluffs many of their own worst hands that will not beat missed draws at showdown. Why? Two reasons:

While Calling Stations call more than GTO, they also raise less, and bluff-raises are an important part of defending against bluffs.
Small bluffs with your very weakest hands do not rely on the BTN folding anything good. It’s enough just to catch them holding trash of their own that failed to improve, trash that would nevertheless beat your trash at showdown, which is why this applies only to your worst holdings.

UTG also makes some larger and more ambitious bluffs with hands as strong as AT, which would beat missed draws like KT and T9 at showdown. But, it’s important to note that in this sim, the Calling Station mixes folds with KQ and AQ facing a pot-sized bet on the river. If you don’t anticipate getting those folds from your human opponent, you should tap the brakes on those more ambitious bluffs and focus on getting more value from your strongest hands.

Conclusion

As is often the case in poker, the “obvious” ways to exploit a calling station are not necessarily the best ways. It’s true that you should generally bluff less against them, but river bluffs with your worst trash can still be profitable, as can semi-bluffs on earlier streets.

“Wait for monsters and then value bet them to death” is simply terrible advice. In fact, you should value bet more thinly against calling stations, and not necessarily for a large size. Both your thinner value bets and your semi-bluffs will perform better against the range that calls a small bet than the range that calls a large one.

There’s also less need to protect yourself against bluffs with trappy checks and blocking bets or pre-emptive turn leads with vulnerable marginal hands. You should play more straightforwardly against calling stations, mostly betting your good hands and checking your modest ones. However, you should lower your standards for what counts as good enough to bet, because your opponent has low standards for what counts as good enough to call.

Author

Andrew Brokos

Andrew Brokos has been a professional poker player, coach, and author for over 15 years. He co-hosts the Thinking Poker Podcast and is the author of the Play Optimal Poker books, among others.