Blockers & unblockers, in poker, are pocket cards in your hand that change the probability of your opponent(s) holding part(s) of their possible range.
Blockers, are pocket cards in your hand that reduce the probability of your opponent(s) holding part(s) of their possible range. For example if you hold the A♠️3♦️ in your hand, and there are three spades on the board on the river, you block the nut flush.
Unblockers, are pocket cards in your hand that do not reduce the probability of your opponent(s) holding part(s) of their possible range. For example if you had a small pocket pair (e.g. 22) on the button, and your extremely value heavy opponent opened UTG on a full ring table, you might be unblocking their entire opening range.
In addition to your pocket cards, cards on the board, can also have blocking or unblocking effects on your opponent’s range. However, it is often more useful to have the blockers or unblockers in your pocket cards, as your opponent does not know you have this information.
Blockers, and unblockers, become more telling the less wide your opponent’s range. For example if an extremely value heavy opponent (and usually passive opponent) on the button raised your UTG open on a full ring table, you might give them a range of QQ+ and AKs. If you had AA, this eliminates a massive part of their range. The math of how blockers affect combinatorics are discussed in a separate article, here at UnfairPoker.com.
When are blockers & unblockers useful in game?
If facing a bet
- When continuing versus a bet, ideally we would want to be blocking our opponent’s value range, and unblocking their bluff range.
- When attempting to catch a bluff (bluffcatching) it is good if your pocket cards unblock your opponent’s bluff range, and block his value range.
When contemplating a bet yourself
- Ask yourself which parts of your opponent’s range you want to target? Are you blocking or unblocking these parts – does this increase or decrease your willingness to bet?
- When we are attempting to bluff, we want to block the hands our opponent will continue with. When we are attempting to bet for value, we want to unblock these hands.
Important Warning about blockers & unblockers
Blockers and unblockers should only be one part of your overall strategy.