Thanks to everyone who participated in What’s Your Play? Flush With Redraw.
I folded, and I don’t think it’s close. The short explanation is #TheyAlwaysHaveIt. Here’s a longer one:
Is This a Bluff-Catcher?
The first question to ask is whether Villain could be raising worse for value. If yes, he’s either making a huge mistake, or you should not fold. Here, I think it’s unlikely that worse raises for value. The only lower flushes possible are 52dd and 42dd, which are unlikely in a raised pot, and in any event would be awfully ambitious raises (the “huge mistake” exception.
Some comments mention straights or overpairs raising. I really don’t see that happening. The mistake here, I imagine, comes from thinking of betting or raising primarily in terms of protection, which is in fact a very secondary consideration here. You can’t “protect” a hand that may well be behind already – the cost/risk of putting in a raise drawing dead far outweighs any protection benefit.
Now you might argue that a recreational player may not think in those terms, but most tend to err on the side of being too passive, especially when it comes to large bets. Not to mention that a player excessively concerned about protecting his hand would probably raise the flop, not the turn.
It’s also worth noting that a player overvaluing weaker hands may also overvalue slightly stronger hands such as Q- or J-high flushes, which is of course bad news for us.
In short, Hero has a bluff-catcher. To decide how to play such a hand, we can start by thinking exploitively about whether this is a spot where Villain is likely to over- or underbluff.
Is Villain Bluffing Enough?
This is quite a difficult spot for Villain to bluff, because (a) he’s raising into a player who is uncapped; and (b) in order to bluff, he needs to get to the turn with a hand that has minimal showdown value and that doesn’t mind re-opening the betting.
That last caveat is important, because, as many comments point out, a bare Ad is a hand without showdown value that sees the turn. If the raise were a shove, enabling Villain to realize the equity of his draw, I would consider that plausible. However, most players will, probably correctly, not raise the Ad here for fear of facing a shove. Again, I think that if he were inclined to raise this kind of hand, he’d be more likely to do it on the flop.
Hero does have blockers to higher flushes, making this perhaps a slightly-better-than-neutral-EV bluff catch against an optimal bluffing strategy. However, there are many reasons to think Villain is in fact underbluffing this spot quite severely.
I was glad to see that nobody really took the bait concerning the straight flush redraw. It, too, could make the hand a slightly-better-than-neutral bluff catcher, but it’s not nearly enough to overcome the situational factors here.
I folded, as did the second player, but the Villain showed Ad Kd anyway. Frankly, I think even this is optimistic on his part (after all, I folded a lower flush). If he’s ahead, he probably has us drawing slim to dead anyway, and he blocks the hand most likely to pay him off (a K-high flush). In his shoes, I would call and probably call the river, though I can actually imagine scenarios where I fold his hand.
In my own shoes, I would not have bet my 9d8d on the river had Villain just called turn, and there’s a good chance I would have folded it to a bet. It really is not that high up in my range, as I can have lots of better flushes as well as most full houses.