What are Blockers in Poker and How Do They Work?


What are Blockers in Poker?

In NLHE, there’s always two cards you know your opponent cannot have – the two you are holding. In other poker variants such as PLO or Stud of course, you can be holding even more. As such, you prevent – or block – them from making their hand. You have a “blocker.” Download WPT Global today and let’s add blockers in to your poker tool box.

Blockers are a relatively advanced concept in poker, and it is important to develop a good grasp of more fundamental ideas first. If you are just starting out, it might be better to spend your time learning more basic aspects of theory – such as preflop ranges, or the value of position – before putting too much emphasis on understanding blockers.

Blockers are a handy tool to have at your disposal and many players do not understand their significance. If you’re ready to incorporate them into your game, they could give you a valuable edge at the tables. Reading this article should provide you with the basic principles, and hopefully help you avoid some of the basic pitfalls. In this article, we’ll look at:

  • What are blockers in poker?
  • How to use blockers when bluffing
  • How to use blockers preflop
  • Can we use blockers for value?
  • Overestimating the significance of blockers


To get an idea of the concept, let’s take a starting hand in isolation, before any community cards are dealt – in this case Spade_1 Diamond_10.

There are four aces and four tens in a full deck of cards, and they can combine with each other in a number of ways – 28 to be precise. It’s a somewhat counter-intuitive result. We hold just one of the four aces, and one of the four tens, yet surprisingly, we block 13 combos – very nearly half of the 28 we started with!

And it doesn’t stop there: our ace of spades blocks four combos of A-K from our opponents’ ranges: Heart_1 Heart_13; Heart_1 Spade_13; Heart_1 Club_13 and Heart_1 Diamond_13. Likewise, we are blocking four combos each of A-Q and A-J. Even our Ten removes certain hands like Diamond_11 Diamond_10 and Diamond_10 Diamond_9 and possibly a few others.

That is a significant chunk of holdings that we can remove from any Villain’s range. As the hand plays through, they may become the kind of combos required to make nutted hands. And when we know that our Villain cannot make those hands, we can use that knowledge to our advantage.

It is valuable information, and it can be applied in a number of ways. But some caution needs to be exercised. We can’t just go barrelling off every time we hold a potentially favorable card. We need to know when to use a blocker, how to use a blocker, and crucially – when not to.

How to use Blockers when Bluffing

Perhaps you can already see how you might use blockers to bluff – but let’s walk through a hand to get a better idea.

In our examples, for the sake of simplicity we will ignore certain aspects such as player tendencies and bet-sizing etc. But of course, in a real-life hand, these are all factors that you will have to consider when deciding whether to utilize a blocker in your hand.

Example 1

Hero opens from the Button holding Spade_1 Diamond_10 and is called by the Big Blind only.

The flop comes Spade_12 Spade_11 Diamond_3 and both players check.

The turn brings the Heart_9.

Hero has picked up an up-and-down straight draw and elects to bet. Villain calls.

The river is the Spade_6, and after a short pause, Villain leads out for around half the pot…

What value hands could Villain have? The way the hand was played, a flush is the most likely candidate – and there are a few possible straights that they might try to get some thin value from.

It is impossible to know exactly what Villain has but there is one hand we do know they cannot have: the nut flush. Holding the Spade_1, Hero can raise here, knowing that he is putting his opponent in a very tricky position.

Even a King-high flush will be put under pressure here, but if we drill down into it, we can see that that hand is relatively unlikely. We block Spade_1Spade_13 (which would raise preflop anyway) but there is another interesting phenomenon at play here: the board itself blocks the Villain from having Spade_13Spade_12 or Spade_13Spade_11. In addition, Spade_13Spade_10 would surely have raised the turn, having made a straight.

So, it is more likely that Villain has made a baby flush, having called preflop with suited connectors like Spade_9Spade_8 or Spade_7Spade_6. A significant raise here will really put them to the test.

It is also worth noting that the ten in Hero’s hand blocks eight combos of straights, making it less likely that Villain is going for thin value with that hand.

But of course, we don’t have to wait until the river to bluff with a blocker. Sometimes we can use card removal to help us far earlier in the hand…

How to use Blockers Preflop

Imagine we are up against a Villain who is 3-betting us constantly when we raise. Our 4-bet value range may consist of A-A, K-K, Q-Q, and A-K. But if we only ever do it with this range, we become far too readable. Villain has an easy fold on the rare occasions we 4-bet and continue to 3-bet us with impunity every other time. We need to find some 4-bet bluffs, but how?

One way would be to choose hands that block Villain’s value range. Say we raise with Heart_1Club_11 and the loose-aggressive Villain 3-bets us again, let’s have a look at a few hands we block:

3 combos of AA

3 combos of JJ

4 combos of AK

4 combos of AQ

7 combos of AJ

This is a considerable portion of hands that Villain might be betting for value, thereby making it more likely that their raise is a bluff. Considering this, Heart_1Club_11 is a decent candidate for putting into a 4-bet bluffing range.

Again, this is just an example to illustrate the effect of blockers. There are many other factors to consider when constructing a bluffing range, and you should definitely not be blindly 4-betting every time you have ace-jack, for example.

Can we use Blockers for Value?

So that’s how to use blockers when bluffing, but can we use card removal to extract value at all?

Well, we can’t really use blockers to bet for value – when we talk about having a blocker, by definition it implies that we don’t have a value hand. Of course, if we hold the nut flush, then we prevent our opponents from having it, but that is really taking the idea too far. Once our hand becomes that strong, the entire notion of blockers is largely irrelevant. There is a related concept however, which can help us with value bets – namely, unblockers.

Imagine the following board run-out:


In this scenario, would you rather be holding Club_1Club_3 or Club_1Club_13?

After a little thought, it should be clear that although is Club_1Club_13 is the higher-ranking hand, Club_1Club_3 will make more money here. The card that we really want our opponent to have is the Club_13, as we will get plenty of calls from a King-high flush. When we hold Club_1Club_3, we “unblock” the king of clubs. 

In the above example – when we unblock Club_13, it becomes a significant part of Villain’s range. Hands like Club_13Club_11, Club_13Club_10, Diamond_1Club_13, Club_13Heart_13 and others, now become combos that will pay us off – not just on the river, but through the streets. Without unblocking the king, this hand may never have got to the river in the first place.

There’s another way that we can extract value by using blockers – and unblockers too. They can help us select hands to bluff-catch with. An interesting quirk here is that our cards can sometimes be used both as blockers and unblockers in the same hand! Let’s see how that might work…

Say we are holding Club_10Heart_10 on a board of Club_11 Spade_9 Diamond_8 Diamond_2 Club_13.

Notice how our hand removes half of the available straights but none of the missed flushes. In other words, it blocks many of Villain’s value bets whilst simultaneously unblocking their bluffs. Our 3rd pair now becomes an excellent candidate to consider as a bluff-catcher.

When you first learn about blockers, their effect can seem negligible. Blocking a few Q-T combos here, while leaving one diamond and one spade open, might appear to be of little consequence. But there is a fine margin between calling too much and too little. Considerations like these can help us walk that line. That said, under-estimating the significance of blockers, is not the worst trap that you might fall into.

Over-estimating the Significance of Blockers

As we have already alluded to, using blockers is a complex, nuanced affair, and there is much disagreement even among pros, about just how much emphasis you should put on them. 

When you first discover a new skill – such as squeezing preflop or overbetting the river – it can be tempting to use that move all the time. This is always a mistake in poker, but never more so than in the case of blockers.

If you start bluffing – or bluff-catching – every time you see a blocker in your hand, you are going to lose a lot of money, very quickly.

Suffice it to say, that blockers should never be your main reason for deciding on any action. Rather, they should be used sparingly, in tight spots to influence a close decision. If you find yourself facing a river bet and it’s a very close call between calling and folding, holding a nut blocker might be one of the factors that helps you lean towards a call.

You should also keep in mind, what variant of poker you are playing and who you are playing it against. The chances are, your game is Texas hold’em. This is by far the most popular poker variant in the world today but unfortunately, it might not be the best game to experiment with card-removal techniques. Games like Pot Limit Omaha; where blocking the nuts has more significance – or 7-Card Stud; where your blocker might literally be face-up, could provide you with more opportunities to utilize your new-found skills.

As for your opponents – if you are just learning about blockers, you are probably going to be playing at the low or micro stakes tables and you are going to encounter a lot of calling stations. There is no point making a river bluff holding the nut blocker if your Villain is going to call you down without thinking. Players at these stakes will struggle to fold an 8-high flush, never mind a king-high one, so choose your spots carefully.


The concept of card removal has become a hot topic in recent years. As the overall standard of poker continues to improve, the more basic ideas are understood by a majority of players, even at lower stakes.

As a result, it has become necessary to incorporate some more ideas into our game, if we wish to maintain an edge at the tables. Understanding when to use blockers could provide just that kind of edge.

However, understanding when not to use them is just as – if not more – important. Many players, including some top professionals, think that the importance of blockers has been over-emphasized, and could cause you more harm than good.

So, if you feel ready to add blockers to your arsenal, by all means go ahead – but exercise caution.