I don't really get it. If we flat, we don't fear a light squeeze behind us because someone with an 18 BB stack just opened in early position. Who's squeezing light here? Someone who wants to lose their chips and go to the movies? If someone 3bets behind us, it's an easy fold, and by flatting we lose less than by 3bet/folding ourselves. And if by flatting we entice someone else to come in and see a flop, that increases our odds of winning a big pot if we flop nice.

Everyone else has said flatting is the absolute worst option here, but it seems to me if we flat we're quite likely to win 20 BB if we flop a set and lose only 2 BB if we don't. That's profitable alone, but factor in that we can win the pot in other ways playing a flop in position against someone who has to fear for their tournament life and it doesn't seem bad at all to me.

I just looked at some rough numbers for a reasonable 3bet/call scenario and it seems to me to be basically exactly breakeven cEV-wise, so it doesn't look very good to me, or at least I can't figure out why it's better than just folding.

This is awful...you 3b an 18bb stack with the plan of folding if he 4b shoves?

I think that your best bet is to shove on him because if you 3b you'll get 4b shoved on a lot of the time.

On the other hand, if you 3b and he flats and you don't flop a set, its almost certain that you are behind because I think that he would only flat TT-QQ there with AQ and AJ maybe in here.

If you don't want to 3b shove, you can always flat and set mine, or hope there are at least 2 undercards otf. Unfortunately your implied odds suck atm, that's why flatting is my 2nd option.

Are you suggesting to flat to set mine vs an 18bb?
And he is basically never calling with that stack, maybe somethimes with AA or KK to check shove any flop.
If you really don't want to shove then fold don't flat.

wow this thread really has legs. 3b/c is > shove because we're 34bb deep even if OR is only 18bb deep. We don't want to shove 34bb into 3 players whose calling range destroys us, but 3b/c allows us to get away cheaply when they wake up with something while accomplishing the same thing against OR. If our stacks were reversed (say we had 18bb and OR had 34) then we'd be happy to shove because we'd be committed to call a 4b against BSB anyway. Any debate here should really be about 3b/c vs open fold.

I don't agree that those are the only options to consider here, but anyway, if we want to evaluate 3b/c, we can probably work out almost exactly what that's worth, chipEV wise. I'll help to get us started! If we assign a cold 4-bet range of TT+ and AK to the three villains behind us, we get 4bet (and thus fold) almost exactly 11% of the time. So if we can work out our fold equity against the opener, and our likely equity against his 4bet shove range, we can see how we do (keeping in mind we only get to play the pot 89% of the time, of course).

I don't think it's an ideal spot by any means for a 3bet especially as the chip leader is still to act behind your 3bet and he is liable to squeeze with KJ/KQ suited type hands any pair (lower than 77 even )if he is an aggressive player to maybe isolate the original raiser as with all the dead money in the pot he is probably getting great value even if the O.R ships all in.Call,fold both seem fine to me but I could be completely wrong.

Alright let me just say my piece about flatting.

You're implying that we're just as likely to see a squeeze as we are a 4b. That isn't true. Most players don't understand how ranges change with an 18bb stack, but anyone whose watched poker on TV knows what a squeeze is. Even if everyone did understand, we'd still be way more likely to get squeezed than to get 4b.

We won't really win this pot in other ways. In reality we're folding to his cbet on 3/4 of flops. We're flopping a set 1/8 of the time and we might win the 16bb he has left, but he might also just give up ott. We'll win other pots occasionally without a set but we'll also stack off trying to win them.

Ok but then let's estimate how often we're getting squeezed if we flat (it'll be a bigger # then 11%). Let's say it's 15%, and suddenly it'll be more common for us to flat/fold pf than it will be for us to flop a set.

So let's calculate a flat: 15% of the time we'll get squeezed and lose 2bb, ~2/3 of the time we'll see a flop and fold to a cbet, losing 2bb. ~10% of the time we'll see a flop and hit a set, let's say we're winning 10bb there. The other 8% we'll see a flop, miss our set, and try to win in some other way, sometimes losing, so let's say we win 4bb there. That makes flatting decisively -cEV, and unlike 3b/calling it's passive and it doesn't balance our range.

Well let's decide between folding and 3bet/get in, which I think is pretty easy to work out. We get cold 4bet 11% of the time, so lose our 3bet size, which means we should 3bet as small as we can get away with without looking weird. We then sometimes win 4.3 BB (pot after villain opens) when villain folds to our 3bet, and sometimes call villain's 4bet shove and get all in with a pot size of 38.8 BB. So if FE is our fold equity and SE is our showdown equity against villain's shove range, our chip EV should be:

what we gain when villain folds: + (0.89(FE)(4.3)
what we win/lose when we get all in: + (0.89)[(SE)(38.8) - 18 ]
what we lose when cold 4bet: - (0.11)( our 3bet size )

Now we can add those up! If we guess villain opens AT+, KQ, and 77+, and folds KQ and AT and otherwise gets all in, then if my pen-and-paper math is ok (maybe not!), we have about 25% fold equity, and 44% showdown equity, which makes this a slightly losing play by a bit less than half a BB. If you think those ranges are off, then maybe it works out better for us, but if our fold equity goes up, our showdown equity will drop. I guess if you think villain is opening pretty wide, this play becomes a lot better.

oh, and I'm almost at 1k posts! Did you guys do anything for your 1k post?

I think you're ranges are off. I'm at least throwing in A8s A9s KJs QJs 66, so depending on his r/f range either our FE or our hand equity goes up or probably both.

I forgot about both 1k and 2k posts. Throw up a HH of a deep run u had or something.

I like the logic of the 3b/c w/ equally deep stacks behind us. I usually just fold to the open however in these spots. If I'm in the BB obviously I put him in.

seems too tight, OR said villain was likely to look for a decent spot to raise.
it's an obv openfold vs most nits who raise like 10% of hands or tighter here and never r/f with this stacksize, but openjam the weakest hands of their range

Yeah

Interesting perspectives

spammer!