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Beginner's Poker Course Part 5: 21,100 Flops, Ranges, & Mixed Strategies

We have gone back and forth between theory and a bit of practicality, discussing just a few hand situations because I felt you needed that. In this article, I want to address those needs again, and we are going to examine some common flop situations.

All the things we have learned up to this point, including EV, GTO, and exploitative play, we will carry into this article, and more generally throughout the rest of this course going forward. They will be integral parts of how we approach these flop situations, and the game in general.

Going from Preflop to Flop

Alright, let's move through the door into the postflop realm, transitioning away from our focus on preflop charts. It's important to note, however, that when transitioning to the flop in-game, we should bear in mind the specific preflop charts that may have been used leading up to the flop.

That may sound a bit confusing and contradictory at first—setting aside the preflop charts while also keeping certain ones in mind. We can illustrate this with an example:

Let's say that we're on the BTN, everyone has folded before us. We are 'playing safe' and are following GTOWizard's button opening range:

We assume the SB has folded to our open-raise. It will be interesting to take a look at what the BB should do according to GTO at this point. This is the chart that shows the strategy for the BB for this specific situation:

This is new for you, so let's pause here and explain why there are three colors in the chart instead of two. This is because the creators of the algorithm (GTOWizard) have chosen to limit the available actions to three. In this specific chart, the BB can fold, call, or raise (3-bet) to 13 big blinds.

You may recall that makers of these algorithms routinely limit the action space because current day computers cannot handle as much as you might think. The game of poker is vast; for instance, in this case, the BB can raise to 4, 5, 6, 7, all the way up to 100, and everything in between those numbers (down to the cents, let's say)! In reality, the BB has a huge action space here! Still, the makers of the algorithm chose the number 13.

Again, they did this because they understood (from earlier studies) that raising to 13 (BB) here is actually a pretty decent sizing. So let's just go with that. The BB can make three actions, and they are represented in the chart above. Red is (still) raising, green is calling, and blue is (still) folding. Very cool.

Let's say the BB decides to call (following the chart); the specific hand 'doesn't matter here', we're just assuming he has a hand that 'has any green in it' within the chart. For instance, a hand like pocket 2's, which has a box that's fully green, makes for a great call in this situation for the BB.

I think I've mentioned this before, but GTOWizard has these kinds of charts for flop situations as well, which is great! Let's take a look:

The first thing that might catch your eye is the fact that 'it's all green' out there. There are also blacked-out parts of the chart now, and the rest is all green boxes!

I chose a random flop of:

The chart shows the BB's strategy for that specific flop. Green means checking here, so he is checking all his hands to the preflop raiser (BTN). That is the GTO strategy for this specific spot that the BB is facing.

The blacked-out spots on the chart are really the 'non-applicable' hands from his overall preflop range, all his possible starting hands. These are all the hands that he either folded or raised preflop; all the non-blacked-out hands indeed represent his 'calling range' preflop after the BTN had opened.

And now we come full circle again. This should make you immediately see why we should be aware of the preflop strategies going into the flop here. All the possible hands the BB could have on the flop here (before the BTN acts) are simply all the hands he was calling with preflop to the BTN's opening range. His preflop calling range becomes his flop range there because all that really happened was that a new flop was dealt; he is carrying over his range street to street.

Range: All the possible hands a player can have in a specific situation.

Similarly, all the hands that the button can have on this flop are all the hands he was opening with preflop. This isn't very hard to wrap your head around, but it's important because these preflop ranges are totally memorizable! They should be one of the most studied subjects for any serious poker player.

What that means is, because we have a good grasp on what the preflop ranges are, or should be, we can have a better grasp on flop situations. Let's have a look at the BTN's strategy after the BB has checked this flop, assuming, with what supposedly was the right strategy, all his hands:

What immediately stands out here is that things look a lot more complex now. As I said, a lot of the preflop ranges are memorizable, but when we get to the flop and beyond, they are not. There are 22,100 different flop combinations to start; on top of that, as we can see in the chart above, the BTN's strategy is already getting quite complicated.

If this is getting daunting to you, that's OK. It is daunting to poker pros as well a lot of the time. Remember, these GTO (Nash Equilibrium) strategies, calculated with AI, do not reflect how the game is played in real poker games.

GTOWizard is a highly advanced tool that offers millions of solutions for many different poker spots, like the one here for the BTN on the ten-five-deuce board. These solutions are not memorizable, as they are highly complex and there are simply too many of them.

What we can do, however, is see important patterns within these charts and improve our general understanding of GTO play in any given situation we might come across. It is possible to get better at poker by using these solver tools on a consistent basis and improving your thought processes by routinely staring at these charts and finding patterns that your brain can manage.

For instance, in the earlier chart, we can see that overpairs highly prefer to bet on this particular board:

Now, if we take the exact same betting history and only change the flop:

We can clearly see that on a 6c5c4c flop:

Pocket pairs jacks through kings are checking most of the time.

And again, all we changed was the flop; the previous betting action stayed the same. Every single flop requires a different GTO strategy, every single one of the 22,100.

So talking about patterns, we see a clear difference in strategy for the 'overpair region' of JJ-KK (jacks through kings) with respect to the two different flops, for that specific betting action:

Now, what's the pattern? Well, in this specific case, we actually have terms for it. The first board is a 'dry board,' and the second one is a 'wet board'.

Let's show an example of another dry board and the button's strategy, with the same betting action:

On this J72 board, pocket jacks is not an overpair anymore but a set, so let's keep focusing on overpairs here. In the zoomed-in part of the chart above, we see that QQ and KK are still betting.

A pattern we can then observe and absorb is that on certain 'dry' boards, overpairs are either 'pure betting' or betting most of the time.

Note: This is a broad generalization but I felt it's a decent example; for instance, there are better ways to segment boards than to only call them 'dry' or 'wet'. But if you take the two extremes of that spectrum, I feel this is a very solid pattern.

Pure and Mixed Strategies

And that was just one simple example. Our brains are amazing at recognizing and storing intricate patterns, especially of things that are important enough to us or that we focus intensely on.

This is why studying with these charts at GTOWizard consistently can be a very worthwhile endeavor. It can shape you up to become a very hard-to-exploit poker boss. You can develop a solid internal GTO baseline to guide your strategic exploits. You will gain a deeper understanding of poker. And the closer you get to GTO, the more ready you will be for higher and higher stakes. Because nowadays, GTO play most likely does matter at the highest stakes online; because these players study; and they study hard.

With that being said, I hope you now have some grounded knowledge about the value of studying GTO strategies. For the rest of the article, I would like to address the open question about how these charts were formed and what the algorithm behind them has done to arrive at these GTO strategies. What is the basis of all this?

The core idea is simple. Bots were put into a poker game together. These bots were programmed in a way that they are very good at exploiting whichever player (other bot) they encounter; they were masters at taking the highest EV actions. They were given full freedom to adjust their strategies, with their overall goal being to beat each other and come out on top as the winner.

And it was war. These bots were fighting it out; each had equal skill. At one point, their strategies became very similar. All of them put together, they were reaching a Nash Equilibrium, and their strategies became Game Theory Optimal.

This is a simple story of how it was done. A complicated algorithm was used, called CFR (Counterfactual Regret Minimization); but the overall idea was that the simulated players (the bots) kept on adjusting to each other until none of them really wanted, or had any incentive to, anymore. That is how they reached the NE. That is how the GTO charts were formed.

That is also how these mixed strategies were formed; we're finally getting to it now. Why do we sometimes do this and sometimes do that? It happens a lot in GTO play in poker. It really is because, if we don't, we become exploitable in poker.

It's like always choosing rock in rock, paper, scissors. No, in order to defend ourselves against exploitation in that game, we should totally mix it up while trying to beat the other. The same is true in poker, but on a much more complex level.

And by the way, the GTO strategy for rock, paper, scissors is:

Later on, when we start talking about more high-stakes situations like playing big pots on the river, this notion of not leaning too much to one thing, or one side if you will, will come back to the table for us.

We will find that balance in poker is just as important as balance in rock, paper, scissors, if and only if you are playing against observant opponents. If you play rock, paper, scissors against a baboon that always chooses rock, well, then you can say 'to hell with that 33 percent' because you will pick paper, as well as his bananas...

In poker, 'bananas' means chips… Exploitative poker wouldn't involve too many mixed strategies, if any; GTO poker includes mixed strategies everywhere and anywhere!

Say we raise first in from the button, and only the BB called. The flop comes:

We have pocket kings with no heart in our hand, let's say:

The big blind checks to us. What is the GTO strategy for us in this situation?