Q & A: River Bet Sizing

A reader recently asked me about a hand, presumably in response to a comment I made about bet sizing on the river when your opponent’s range is defined as a bluff-catcher:

“What do you think would be optimal sizing on this river? I feel like this is a spot where his range is capped and is bluffcatching a lot.

Full Tilt No-Limit Hold’em Tournament, 10/20 Blinds (9 handed) – Full Tilt Converter Tool from FlopTurnRiver.com

MP3 (t2970)
CO (t2890)
Hero (Button) (t2580)
SB (t2760)
BB (t2850)
UTG (t3080)
UTG+1 (t5900)
MP1 (t990)

Hero’s M: 86.00

Preflop: Hero is Button with 7, 7
UTG bets t60, 4 folds, Hero calls t60, SB calls t50, BB calls t40

Flop: (t240) A, 2, 6 (4 players)
SB checks, BB checks, UTG checks, Hero checks

Turn: (t240) 7 (4 players)
SB checks, BB checks, UTG checks, Hero bets t160, 2 folds, UTG calls t160

River: (t560) 6 (2 players)
UTG checks, Hero ?

The game theoretically optimal bet size would most likely be all in. In practice, most people will probably fold exploitably often to such a massive overbet, which makes it potentially appealing as a bluff but not the most profitable size for a value bet.

More broadly, I think it’s important to think about the hands that are likely to pay you off. In this case, the most obvious second-best hand for Villain to have is either a weak A or a pocket pair. You’d love it if he were getting really trappy with two pair or a worse set, but that is such an unlikely prospect that you shouldn’t plan around it, not to mention that it may not matter what you do if he is really that strong.

On the river, it should be clear to both you and Villain that he can only beat a bluff. This is true almost no matter what bet size you choose. Thus, no matter what you bet, he is faced with the same problem of guessing at your bluffing frequency.

If you have some reason to believe that he will interpret an overbet as never a bluff, then you should choose the largest amount for which you think he will still give you credit for bluffing. You should also overbet bluff a lot.

Most likely, though, you don’t really know how he will interpret an overbet. The GTO play is for him to call in proportion to the pot odds that he is getting, and unless you have information to help you determine how he will deviate from this, then you should assume for your purposes that that’s what he’s doing. In that case, bigger is better. This is one of the morals of my most recent Tighty McNuts adventure.

I find that especially in tournaments there is a point at which people just don’t hero call at all. I do try to exploit that with bluffs, but in this case I think a shove is just not going to get called. I would bet something in the neighborhood of 800-1000, slightly less than twice the pot.

For what it’s worth, I would also bet bigger on the turn, probably pot. There is such an obvious second-best hand (pair of Aces) that most people are going to auto-call here that you don’t need to worry about what you’re representing. Unless you overbet the pot, most people are going to click call without even thinking about what you might have when they have OMGTOPPAIR and have checked twice.

3 thoughts on “Q & A: River Bet Sizing

  1. Maybe it’s the stakes I play (10 and lower) but everytime I over bet the river people fold. It’s like the new over bet is the new “call me bet”. People mistake it for the nuts.

  2. Is there some reason he can’t have AA or 66 here? I can’t think of one, especially in the early stages of a tournament where many players are willing to trade a fair chance of winning a modest pot for a small chance of winning a big pot.

    Part of the equation is how often he will have one of these hands versus how often he will call with a bluff-beater.

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