River Bluff Catcher: When to Call a Bet on the River
A river bluff catcher is a hand that beats every bluff and loses to every value bet. Call when the bettor bluffs at least call ÷ (pot + bet + call) of the time: 25% against a half-pot bet, 33.3% against a pot-size bet, 40% against twice the pot. Prefer the catchers that block value hands and leave the bluffs in the bettor's range.
Second pair facing a river jam
In the big blind with K♣T♣, the board runs K♦ 8♠ 4♥ 3♦ A♣. You check the river and the button jams 45bb into 22bb. Fold or call?
How many bluffs a call needs
The river cannot improve your hand, so the only question is how often the bettor is bluffing. The call breaks even when that share equals call ÷ (pot + bet + call):
| River bet | Bluffs needed for a call |
|---|---|
| half the pot | 25% |
| 75% of the pot | 30% |
| the pot | 33.3% |
| 150% of the pot | 37.5% |
| twice the pot | 40% |
See the answer
In the first spot, a 45bb jam into 22bb asks you to call 45bb to win 67bb: 40.2% bluffs are enough. Against a polarized jam, the bettor's range is split between strong hands and missed hands, and K♣ removes some of the kings that beat you.
The same numbers, seen from the defense, are in minimum defense frequency.
Top pair after the draw missed
In the small blind with Q♠J♠, you check-called J♦ 8♠ 5♣ and the 9♠ turn. The river is the 2♦ and the button bets 80% of the pot. Fold, call or check‑raise all‑in?
See the answer
An 80% pot bet needs 30.8% bluffs for a call. Your top pair beats the missed draws, but raising all‑in only gets called by better hands: the hands that would call are exactly the ones that beat you. Your spades remove some missed draws, but top pair stays at the top of your bluff catchers.
Choosing between bluff catchers
| Your hand | Call? | Why |
|---|---|---|
| beats every bluff, blocks value hands | yes, first | fewer value combinations left |
| beats every bluff, blocks missed draws | less often | removes the bluffs you want to catch |
| loses to some bluffs too | rarely | pays off value and does not even win against every bluff |
| beats some value hands | that is a value hand | consider raising |
Keep going
- The same threshold from the bluffer's side: how often a bluff must work.
- Pot odds before the river: pot odds.
- More river decisions: what would you do.
- How the bet got here: the double barrel.
- One spot every day: the daily poker puzzle.
- Betting a hand that is only slightly ahead: the thin value bet.
- When the bet is bigger than the pot: the overbet.
- Calling a river jam with nines: how to play middle pairs.
- Judging a call against a whole range: poker range.
- What a bluff catcher beats, by range: polarized vs merged range.
- The call's indifference point: GTO poker.
- A river bet made before you can act: the donk bet.
- The three river decisions: river strategy.
- How many bluffs a river betting range holds for each size: the bluff to value ratio.
- One pair below the top: second pair, a hand to check and call.
- The five checks before any bluff: how to bluff in poker.
Sources
- Every percentage on this page is computed from the formula call ÷ (pot + bet + call), checked on October 10, 2026.
- The answers to the spots follow rules written by the app's author; they do not come from a solver.