Bluffs and bluff catchers: when to bluff, with which hands, and when to call

Bluff, semi-bluff and bluff catcher

• Pure bluff: you have almost no equity when called. It wins only through folds; typical on the river with a missed draw.
• Semi-bluff: you bet a hand that is behind now but can improve, such as a flush draw. It wins through folds and, when called, sometimes on later cards.
• Bluff catcher: a hand that beats the opponent's bluffs and loses to their value. Top pair on a river where the opponent bets big is usually one.

In 6-max cash, big bluffs show up mostly on the turn and river, when ranges are already polarized: the bettor has very strong hands or air, and the caller has medium hands.

When to bluff: fold equity

A pure bluff needs the opponent to fold at least alpha: bet / (pot + bet).

Example: the river pot is 20 bb and you bet 15 bb. Alpha is 15 / (20 + 15) = 42.9%.

• If the opponent folds 50%: EV = 0.5 × 20 − 0.5 × 15 = 2.5 bb. The bluff wins.
• If they fold 35%: EV = 0.35 × 20 − 0.65 × 15 = −2.75 bb. The bluff loses.

Fold equity goes up when:

1. Your story makes sense. The cards that came improve your range more than theirs (an ace or king on the turn for the BTN opener).
2. The opponent's range is capped. If they checked the turn in position, they rarely have the nuts.
3. You face a single opponent. Multiway, someone almost always has something.
4. The opponent can fold. Against a calling station fold equity is close to zero: there is no profitable bluff, only a value bet.

Semi-bluffs: draws that bet

A semi-bluff combines two sources of EV: folds now and cards to come. On K♥8♥3♣ with A♥5♥ you have the nut flush draw: 9 outs. When called, you complete the flush 19.1% of the time on the turn (9 / 47) and 35.0% by the river.

That is why a semi-bluff needs fewer folds than a pure bluff: when fold equity fails, you still have equity. The best semi-bluffs have:

• Strong draws: nut flush draws, open-enders, combo draws.
• Overcards that can also win when they hit.
• Blockers to the hands the opponent will call with.

On the turn, with one card to come, the same draw drops to 9 / 46 = 19.6% equity: sizing and fold equity matter more there.

Blockers: which hands to bluff and which to call

A blocker is a card in your hand that removes combos from the opponent. When bluffing, you want hands that block their calls and do not block their folds. When calling, you want hands that block their value and do not block their bluffs (an unblocker).

Example: the board runs out 10♦8♥3♥2♣5♠ and the heart draw missed. The opponent bets big on the river; their natural bluffs are missed hearts such as K♥Q♥ or 7♥6♥.

• With A♣10♠ you have top pair and no heart: you remove none of their bluffs. That is the best bluff catcher.
• With A♥10♣ you have the same strength, but the ace of hearts removes every missed nut flush draw. That call is worse.

Flip it around: if you are the one bluffing that river, a missed draw with no showdown value such as K♥Q♥ is a better bluff than a hand with some showdown value, which can win by checking.

River value-to-bluff ratio

With a polarized range, the value-to-bluff ratio that makes the opponent indifferent with a bluff catcher depends on size. Bluffs can be bet / (pot + 2 × bet) of the betting range, the same equity the caller needs:

Betting bigger allows more bluffs per value combo, but also makes each bluff more expensive. If you have 12 value combos and bet pot, you can add up to 6 bluffs. Add more and the opponent profits by calling with any bluff catcher.

How to pick a bluff catcher and when to call

Facing a pot-sized bet (20 bb into 20), calling costs 20 to win 40: you need 20 / (20 + 20 + 20) = 33.3% equity. MDF is 20 / 40 = 50%: if you fold more than half your range, any bluff by the opponent profits.

MDF is a reference against opponents who bluff well. Against real opponents, the question is how many bluffs they have:

• If the opponent bluffs 1 time in 5 (20%): EV of calling = 0.2 × 40 − 0.8 × 20 = −8 bb. Fold even if that puts you under MDF.
• If they bluff 1 time in 3 (33.3%): EV = 0. You are indifferent.
• If they bluff more: calling profits.

At micro and small stakes, many passive players barely bluff big river bets. Against them, folding top pair to an overbet is correct. Save the hero call for opponents with proven bluffs and for hands that unblock those bluffs.

Common micro stakes mistakes

1. Bluffing players who call everything. Against a calling station, bet thin value instead and drop the bluffs.
2. Bluffing multiway. With two or three opponents, the bluff needs all of them to fold.
3. Bluffing with no story. A big bet on a river that changes nothing, after checking the turn, rarely convinces anyone.
4. Calling out of curiosity. "I want to see what they have" is expensive against a player who does not bluff.
5. Picking bluffs with showdown value. A hand that sometimes wins by checking does not need to bluff.
6. Bluffing small on the river against players who call any small bet: the size does not generate folds.

How to practice it

Before every river bluff, say two numbers out loud: the alpha of your size and which value hands you would have with the same line. At POKER AULA, thin value, bluffs and bluff catchers are covered in the Intermediate level, MDF, alpha and blockers in Upper Intermediate, and polarized river play in Professional. The Calculator gives you alpha, MDF and value-to-bluff for any size, and in Training you decide whether to bet, call or fold with the correction and THE WHY. You can try it with the 48-hour free trial.