ConceptsRanges and boards
Blockers and unblockers
Your cards are not in anyone else's hand: holding one removes the combos that need it.
What it is
A blocker is a card you hold that makes certain hands less likely for your opponent, because they would need that same card. Holding the A♠ means there are 3 combos of AA left instead of 6, and 12 combos of AK instead of 16.
The other side is unblocking: not holding the cards of the hands you want your opponent to have. A bluff works best when you do not block the hands that fold.
Why it matters
Blockers are how close decisions get made. When two hands are worth about the same, the one that removes more of the opponent's strong hands is the better bluff — and the one that removes more of their bluffs is the worse bluff-catcher.
They matter most when ranges are narrow — late in a hand, or after several raises preflop — because each removed combo is a bigger share of what is left.
The board blocks too: a king on the flop leaves 3 combos of KK, not 6.
The maths
A pocket pair has 6 combos with all four cards available, 3 with one removed, and 1 with two removed.
An unpaired hand's combos equal the cards left of its first rank times the cards left of its second rank.
Worked example
A 4-bet bluff with A♠5♠
Your opponent continues against a 4-bet with QQ+ and AK: 6 + 6 + 6 + 16 = 34 combos.
- Your A♠ removes half the aces: AA drops from 6 combos to 3.
- AK drops from 16 to 12 (3 of 4 suited, 9 of 12 offsuit).
- KK and QQ are untouched: 6 each.
- Their continuing range falls from 34 combos to 27 — about 21% fewer.
That is why small suited aces are classic 4-bet bluffs: the ace removes a big share of the hands that continue, and the hand still has some equity when called.
Try it
Pick your two cards (and a board) and see how many combos of each class are left.
Common mistakes
- Bluffing because of one blocker when the opponent's range is still mostly strong hands.
- Blocking the hands that fold. A bluff with the cards your opponent would fold makes them more likely to have something that calls.
- Forgetting the board: cards on the table remove combos for both players.
Related concepts
- Bluff-catchingCalling with a hand that beats only bluffs: the price says how often they need to be bluffing.
- 3-bets and 4-betsThe first re-raise before the flop, and the re-raise after it: building pots with value and taking them with fold equity.
- RangesNobody holds "a hand" — they hold every hand they would have played this way, and you decide against all of them.