I haven't been posting in this thread because usually other people have been saying what I would have said. But I found the debate over the turn bet sizing and planning to be interesting enough that I went ahead and actually did some math (as opposed to using my intuition to get a ballpark estimate). Full disclosure: my intuition in this hand told me that the bigger turn bet followed by a river check behind would be a better play than betting small on the turn and then going for a third street of value on the river.
To simplify the math, let's say that the "small bet" is a 1/3 pot bet offering 4:1 pot odds, and the "big bet" is a 2/3 pot bet offering 5:2 pot odds.
Now, let's say that *Split*'s assumptions are basically correct, as follows: if we make the small bet, villain calls with a range that includes decent (8+ out) draws, as well as some Qx and Jx hands, but if we make the big bet, villain folds the Jx hands.
For the small bet, I gave Villain the following range:
KT, T9, A
K
, A
T
, T
8
, 9
8
, 5
4
, QT, AJ, KJ, JT, J9. (So far I'm not considering hands that already have us beat.)
Against this range, we have an equity edge of about 85.5% to 14.5%--we are just under a 7:1 favorite. So if this entire range calls us getting 4:1 odds, we theoretically ought to profit.
There are 3 problems here that I see:
1) If we make the small bet, we'll probably want to get a third street of value on the river. That means we open ourselves up to losing one or more bets when we are outdrawn. If this is the range that calls us on the turn, we will still profit from the call as long as we don't lose 3 times our bet on the river.
2) I didn't include hands that beat us, such as AQ, slowplayed QJ and 44, and 64 that just made 2 pair. By betting small, we could level ourselves into calling if those hands raise us (or, we just fold and lose our bet 100% of the time). That slashes the profitability of this play, but by how much, I can't be sure (it depends on things like bet sizing and how stubborn we are). EDIT: This could be a wash when we consider that sometimes we really do get a third street of value from a worse hand.
3) We don't know that the assumption that Jx calls us is correct. It's possible that this villain folds Jx to any bet and sizing doesn't matter. If that's the case, then the range of hands we beat that call the turn could look like this:
KT, T9, A
K
, A
T
, T
8
, 9
8
, 5
4
, QT, A
J
, K
J
, J
T
, J
9
Against this range, our equity edge is about 81.5% to 18.5%--we've dropped from a 7:1 favorite to roughly a 4.5:1 favorite. If we are offering 4:1 odds, then we just barely profit on the call, and the bet is unprofitable if we give any implied odds on the river. If we mistakenly assume that a wider range is calling the turn, and we go for a third street of value on a lot of rivers, that makes this small bet sizing wrong in retrospect.
If we take this narrower range of draws and offer 5:2 pot odds and check behind most rivers, though, that's definitely profitable--we offer worse pot odds, plus we aren't offering implied odds to any hand that checks to us if we always check behind. (Plus we can more confidently fold to a raise--while I agree that this should not be the deciding factor in sizing, I do think it can be useful as a small factor.)
So it seems like it matters a great deal whether we can count on Villain to call a small bet on the turn with Jx, but not a big one. If Villain calls both sizes with Jx, betting bigger is obviously better. If Villain folds Jx to both bet sizes, betting bigger is obviously better. Only if Villain will call a small turn bet with Jx, but fold to a big one, is it possible for the small sizing to be correct. (The bigger bet may still net more profit just by virtue of being bigger. But this post is long enough already...)
I think one possible reason for my intuition that I want to make the bigger bet here is that rarely do I know my Villains well enough to know whether these very specific conditions for a small bet to be good are being met.
EDITED TO ADD: Welcome to the forum *Split*; I hope you stick around.
Last edited by CallMeVernon; 06-01-2012 at 06:13 PM.