What is Unblocking in Poker & Why Does it Matter?

I’m pretty sure you’ve heard of blockers, which have been all the rage in poker for a few years now…

…but have you heard about unblocking?

Unblocking is a relatively fresh poker concept that greatly impacts how you should build your strategy in certain situations. This will be the focus of today’s article.

Specifically, here is what I’m about to cover:

• What Are Blockers?
• What Does Unblocking Mean?
• Why Does Unblocking Matter?
  • Unblocking and Value-Betting
  • Unblocking and Bluff-Catching
  • Unblocking and Bluffing

Before diving into unblocking, let’s make sure everyone is on the same page by running through what blockers are.

This article is marked as advanced. If you’d prefer easier reading, check out our introductory articles here or intermediate articles here.

What Are Blockers in Poker?

A blocker is a card held by a player that makes it impossible (or less likely) for an opponent to have a hand that includes that card (or a card of the same rank). Also known as card removal or combinatorics, blockers are a fundamental concept in poker game theory.

Definition from the Upswing Poker Glossary.

For example, if you hold A♠ K♥ and the board reads J♠ T♠ 2♠ 5♥ 6♦, it’s impossible for your opponent(s) to have the ace-high flush as you hold the A♠ blocker. Similarly, if you hold 7♥ 7♦ and the board reads 8♦ 6♥ 5♦ Q♠ K♠, it is significantly less likely that your opponent has a straight because your hand blocks half of the possible combinations of 9-7 and 7-4.

Further reading: Boost Your Winnings by Using Blockers in These 3 Common Spots

What Does Unblocking Mean?

Unblocking refers to holding a card that does not lower the probability that an opponent has a certain hand. In other words, an unblocker is a card that makes hands that don’t contain that card more likely.

A card is oftentimes both a blocker to some part of the opponent’s range and an unblocker to another part of that opponent’s range. For example, if you hold 7♥ 7♣ and the board reads 8♦ 6♥ 5♦ Q♠ K♠, your hand blocks the possible straights while also unblocking the missed flush draw (since you don’t hold a diamond in your hand).

If you’re confused, don’t worry. The examples in the following sections will make it clearer.

Why Does Unblocking Matter?

Unblocking and Value-Betting

Before I answer the question “why does unblocking matter?”, I want you to answer a different question first.

Suppose you raise preflop from the Button and the Big Blind calls. You bet on the flop and turn, both of which your opponent calls. You’re now on the river.

On a final board of K♥ 9♥ 7♣ 6♦ J♠, would you rather find yourself value betting on the river with K♠ K♦ or 9♠ 9♦?

I’ll give you a few lines to think.

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Ready? The answer may surprise you…

Despite being a worse hand in an absolute sense, 99 has a much higher expected value (EV) than KK in this situation.

When you hold KK, you block a lot of the hands that would call you down (such as KJ, KT, K7-suited, K6-suited). When you hold 99, all those Kx hands are unblocked. Thus, you win a lot more chips from the pot on average. 

Here is a PioSolver simulation of this scenario which proves that this is actually true:

This screenshot shows the EV of each hand for each option. When using the solver’s preferred bet size of ~1.5x the pot, KK has an EV of 65.83 chips (blue arrow) while betting the same amount with 99 has an EV of 73.03 chips (red arrow). That’s an 11% increase in EV when betting with 99.

Unblocking and Bluff-Catching

Unblocking is also important when it comes to bluff-catching. When you’re deciding whether or not to call a bet with a bluff-catcher, you should always consider the blocker effects of that hand.

From the blocker standpoint, a good candidate to call would:

1. Block the opponent’s value hands
2. Unblock the opponent’s bluffing hands

To exemplify this, let’s look into another hypothetical scenario.

The Small Blind raises preflop and you call from the Big Blind. The flop comes J♥ 9♥ 5♣. The Small Blind c-bets 33% pot and you call.

The turn is the 6♠, he bets 66% pot, and you call.

The river is the 2♠ and he c-bets 66% pot.

Which of these two hands is the better bluff-catcher: Q♠ 9♠ or 9♠ 4♠?

I’ll give you a few lines to think again.

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…

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In this case, 9♠ 4♠ is a better bluff-catcher even though it’s the weaker hand in terms of absolute strength (i.e. a Queen kicker is better than a 4 kicker).

There are two reasons why the 94s is the better bluff-catcher:

• The Small Blind wouldn’t value bet a hand that beats 94 but loses to Q9, so the weaker kicker is not relevant in that sense.
  
• The 4♠ unblocks potential bluffs such as KQ, QT, Q8, or Q7. Meanwhile, the Q♠ blocks all of those possible bluffs.
  

Here is another PioSolver simulation to back up my words:

And here’s how 9♠ 4♠, specifically, is played by the solver:

So, 9♠ 4♠ is a call 100% of the time, while Q9-suited is folded 90% of the time. The power of unblockers at work!

Unblocking and Bluffing

Last, but not least, unblocking also comes in handy when choosing hands with which to bluff.

The idea is that a good bluff candidate is one that:

1. Blocks the opponent’s calling and bluff-raising ranges.
2. Unblocks the opponent’s folding range.

Let’s take a look at a final scenario.

You raise preflop on the Button and the Big Blind calls. The flop comes 8♠ 5♠ 2♣. You c-bet 75% pot and get called.

The turn is the 9♦. Your opponent checks and calls your 75% pot bet.

The river is the 3♥.

With which hand should you rather bluff: Q♥ T♥ or Q♠ T♠?

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…

…

Ready?

You’re much better off bluffing with Q♥ T♥. Holding hearts instead of spades when the spade draw has missed has a great impact on your opponent’s calling range.

Q♥ T♥ unblocks the many missed flush draws the Big Blind could have, such as T♠ 7♠, T♠ 6♠, T♠ 2♠, Q♠ T♠, Q♠ 7♠, Q♠ 6♠, Q♠ 4♠, Q♠ 3♠, and Q♠ 2♠. All of these hands will almost certainly fold to a river bet. Q♠ T♠ blocks all of these hands, which makes it slightly more likely the Big Blind has a made hand with which he will call.

Take a look at the bottom right of this PioSolver sim which proves that this is indeed correct:

Here, you can see that the solver is always triple barreling with Q♥ T♥ when it gets to the river with it (which is not all that often). On the other hand, the solver is never triple barreling with the Q♠ T♠ because of its terrible blocker effects.

Related quiz: [QUIZ] Do You Know Which Hands to Bluff With?

Final Thoughts

You might have noticed that all of my examples were river scenarios. This was on purpose because unblocking effects have the greatest impact on river decisions because that’s when the ranges are most narrow.

This blocker/unblocker business can be a bit confusing and tough to follow, especially considering that they matter most when the pot is at its biggest. But now you are equipped with the basic knowledge on how to improve in these crucial spots.

That’s all for this article guys! I really got a kick out of writing this one. I hope you enjoyed it and that you learned something new.

As usual, if you have any questions or feedback please let me know in the comment section down below and I’ll do my best to answer.

Here’s a related article that I suggest reading next: What are Reverse Implied Odds & Why Do They Matter?

Till’ next time, good luck, grinders!