blocker

A blocker is a card in your hand that reduces the probability your opponent holds a specific combination. Blocker effects are a precision tool in modern range analysis.

Detailed Explanation

There are only 52 cards in the deck. If you hold the Ah, your opponent can't also have the Ah. When you analyze their range, this "removal of certain combos" is the blocker effect.

Typical examples:

• Holding Ah: opponent's nut flush (Ah + another heart) is impossible
• Holding Ks: opponent's KK drops from 6 combos to 3 combos
• Holding A5s: blocks the opponent's strong aces (AK / AQ etc.) and reduces the density of their 3bet range

The opposite is the unblocker: your cards don't block the opponent's bluff range, meaning they are more likely to be bluffing.

Common Use Cases

• River bluff selection: pick hands that block the opponent's value range and don't block their bluff range as your bluff candidates
• Bluff catching: pick hands that unblock the opponent's value range as calls — avoid hands that block their bluffs
• Preflop squeeze: use weak hands with an ace or king blocker (A5s, K9s) as semi-bluff 3bet candidates

Common Mistakes

• Over-relying on blockers: blockers are only small adjustments (a few combos), not enough to overturn dominant range judgment
• Ignoring two-way blocking: you block the opponent's range, but your range is also blocked by them — think symmetrically
• Only looking at blockers, not unblockers: high-level river decisions need both sides considered