Blockers - Poker Strategy

November 22 2009

Blockers

are cards that you are holding in your hand and your opponent therefore cannot have. The fact that your opponent is not holding these cards can limit his possible range in some cases. Thinking about blockers is especially important in 3-bet positions and on boards with draws, and it often occurs during push-or-fold phases in tournaments, but should also be thought about when playing cash games. We will start off by looking at the consequences of holding blockers in postflop situations.

Postflop situations

In Texas Hold'em every player receives two cards and a maximum of five community cards are dealt. These two cards enable you to make a possible 1326 different combinations, which can be split into the following groups.

- 78 suited hands (for example AKs)

- 78 offsuit hands (for example AKo)

- 13 pairs (for example 22)

Each one of these groups can be split up into sub-groups:

- Each suited hand has four possible combinations (for example AhKh, AcKc…)

- Each offsuit hand has twelve possible combinations (for example AhKs, AsKh…)

- Each pair has 6 possible combinations (for example AhAd, AcAs…)

So, what blockers does your hand provide? An offsuit hand (for example ) blocks a total of 101 combinations. This means that every offsuit hand blocks a total of 101 from the 1326 possible combinations. A suited hand also blocks 101 combinations while a pair blocks 91 combinations. This is, of course, a large number of hands, but in reality the range of your opponent is much more limited. You might be blocking the combinations of K2o, but this hand is rarely part of a player's range. Usually you can put your opponent on a tighter range, after which you can then eliminate a couple of combinations from this range. What is much more relevant is how many combinations that result in pairs, off suit hands and suited hands fall within this range.

Example

With the following hand you made it to the river:

Seat 1: Villain ($99 in chips)

Seat 2: Hero ($101 in chips)

Seat 3: Folder 1

Seat 4: Folder 2

Seat 5: Folder 3

Hero: posts small blind $0.50

Folder 1: posts big blind $1

*** HOLE CARDS ***

Dealt to Hero

Folder 2: Folds

Folder 3: Folds

Villain: raises $2 to $3

Hero: calls $2

Folder 1: folds

*** FLOP ***

Hero: checks

Villain: bets $4

Hero: calls $4

*** TURN ***

Hero: checks

Villain: bets $10

Hero: calls $10

*** RIVER ***

Hero: checks

Villain: bets $24

Hero: ?

What is villain betting with on the flop, turn and river? He placed a continuation bet on the flop and kept on barrelling when scarecards appeared. The range of villain could be: a number of made hands (22, 99, TT, AA, 9T, A2, A9-AK), a number of pure draws (JQ, 78), a couple of draws with a pair (, , ) and some complete bluffs. How many possible combinations does villain have in total and how does this number change when we include your hand in the equation?

So, by being in this specific hand with you are blocking 39 of his 135 possible combinations in his range. This doesn't include the possible bluffs. Lets say you decide to call. In this case it would be interesting to know how many of the combinations that you're you are blocked by your hand:

Of the 79 possible combinations of hands that beat you, you are blocking 24 of them with your hand. This means that you are blocking 30% of the range of hands that beat you and 28% of the hands that you are still ahead against. This makes a substantial difference if you decide to call with a hand that has blockers compared to calling or bluffing with a hand that has (almost) no blockers.

Pre-flop: All-in?

In tournaments, the thought about having blockers or not comes up regularly, but then often in the form of live cards. Players will tell themselves that if they go all-in with 65s and they get called, they will almost always have live cards. If your cards have no blockers, then they are live and have outs. Therefore it is sometimes better to push with 76s than with QJo, because you are more likely to have live cards. On the other hand your opponent might fold more often, because the number of combinations in his range are limited by the blockers you could be holding.

In this example three more hands against different ranges are being discussed.

The range always represents a number of hands. The number of combo's implies the number of combinations of two cards within that range. There are four different hands, with AKo being slightly less interesting in terms of blockers because you are often happy enough to get your money in preflop with AK, although you are still a slight underdog against a pair. We are assuming here that you 3- or 4-bet and your opponent pushes all-in with the following ranges.

So, lets say your opponent pushes with a tight range after you 3- or 4-bet. This tight range (AK, JJ-AA) includes 40 combinations and therefore makes up 3.0% of all possible combinations. If your opponent decides to push and you are holding AKo, then he will only push with a range of 27 combinations, or 2.0% of all possible hands. Your blockers therefore reduce his range by 1% (down from 3% to 2%). In other words, you are blocking one third of his range. The result will be that your opponent will decide to fold against you 33% more often. Then again you are holding AKo, so more often than not you will be happy to go all-in. So the question is how this changes with other hands.

When holding QJo you are blocking 6 combinations from his tight range (JJ and QQ). Against his push range you will always be a big underdog, but you do limit his push range by going all-in. The number of hands our opponent will now push from his tight range went down from 3% to 2.6%. If you are holding the Ace-blocker (for example with A7o), he will only push with 2.5% of hands and if you're holding 65s this has no effect what so ever.

Playing against a tight range can often be complicated if you want to make use of blockers, but with his range increasing, so does the importance of the blockers. A range of AQo+, AQs+ and TT+ includes 62 combinations and therefore 4.7% of all possible hands. With QJo you are blocking 10 combinations and with A7o you're blocking 11 combinations. This means that he will only push with 3.9% and 3.8% of his hands. As you can see you have now reduced his push-range against you (re-)raise by 1/6. A weak Ace will have about the same effect as two broadway cards such as QJ. The higher the broadway cards, the bigger the effect they will have on the push range of your opponent. Below you can see the remaining push range as a percentage of all hands:

You could also use the above for normal 3-bet ranges. If, for example, you are playing against the "very loose" range, you can see that your opponent will fold 14% more when you're A7o compared to when you hold 65s. On the other hand you can see that the larger the push range of your opponent, the less important your blockers become. Against a tight range you will block around 21% of your opponents combinations with QJo, while against a "very loose" opponent you would only block 16% of all combinations. Therefore you say that the looser your opponent, the fewer hands you block when holding two broadway cards. When it comes to low suited connectors you will need your opponent to have an extremely loose range in order to be blocking any of his combinations.

This was my article about blockers. I hope this article helped you understand the importance of this concept when playing Texas Hold'em. Success at the tables!!

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