What If My Opponent Chooses The Wrong Sizing?

If you’ve ever pondered how to exploit someone choosing what you think to bet the wrong bet sizing for the situation, this is the article for you.

Today we’re going to focus on how to exploit an opponent who cbets too frequently for a small sizing on a board where he/she should be using a bigger sizing and making more use of his/her check button.

My goal today is to give you a workable strategy when facing these kind of players.

The more solver work we do, the more we see where the population is playing very far from GTO. In these spots, it can be very useful to work out what exploits you can make to develop a higher EV strategy from using a GTO approach alone.


One such trend in MTTs among low- and mid-stakes players is to use a one-size-fits-all cbetting strategy of betting range for 1/3 pot on all flop textures. While this works really well against weak opponents who will not check raise aggressively enough or float wide enough, it starts to be an inferior strategy versus competent, aggressive opponents on specific boards, like the low board we’ll talk about today.

Here’s the situation:

You’re playing a $22 tournament. The Button (30bb) opens to 2.1bb and only the BB (also 30bb) calls. The flop comes 6s 5d 2s, the BB checks and the Button bets 1/3 pot. You’ve observed him make this same bet on lots of different boards and through your own study, you know that this is the wrong sizing to choose on this board. You also believe that he’s using this sizing so he can just bet his entire range and not have to worry about developing a checking range.

What do you do?

First let’s take a look at villain’s cbetting strategy on this board.

What Should His Flop Strategy Look Like?

On this board, facing a solid, aggressive opponent, the Button should check roughly 60% of his range and bet 40% of his range using a big sizing (70% pot). His betting range mainly consists of two pair (65s), overpairs (KK-77), most of his 6x hands (like A6s or K6o), combo draws (like As4s or 9s8s) and about half of his flush draws (e.g. Qs9s or Ks7s). His checking range includes the other half of the flush draws (like AsQs and KsJs) and all the other hands.

He should do this for a couple of reasons:

1. The equities between the two ranges run very close together, so there’s no clear equity or ‘range advantage’

2. The big blind has more nut combos (2pair+) and so has a ‘nut advantage’

What Should Our Strategy Look Like Versus a Cbet?

Dark red = jam, Pinky red = raise, Green = call, Blue = fold

Versus the cbetting strategy above, we can actually only check-raise about 7% of our range, mixed between 4% jams and 3% ½ pot raises, while calling 54% and folding 39%.

When studying these spots I like to use this table to group together hand strength:

But what do we do when our opponent bets range for a small sizing (say 1/3 pot)?

Exploiting Our Opponent

Before reading the rest of the article, it’s worth thinking about what you would do to exploit such an opponent. Should you raise more? What kinds of hands should you raise? Should you call more? Are there any hands that move from a call to a raise or vice-versa? Or are there some hands that were folded before that now become calls or even raises?

Dark red = jam, Pinky red = raise, Green = call, Blue = fold

Look at that sea of pinky red! That means we can now go absolutely bat-shit crazy and start raising over 50% of our range. We’re now calling around 31% and only folding 12%.

Let’s use that same table from earlier to compare the two strategies:


As you can see, the strategies are very, very different. By breaking it down into hand strength, hopefully you can see exactly how the strategies differ and begin to implement a more aggressive, exploitative strategy versus someone choosing the wrong bet size and flop strategy on these low boards.

I definitely recommend looking at other low boards and different stack sizes to build a better understanding of the ideas we’ve talked about today.

I hope you enjoyed this article. Please let me know if you have any questions or feedback.

Good luck

Gareth James

Founder and Head Coach, MTT Poker School