This hand comes from a 1/2 NL game. The SB was a tight, passive, and unimaginative player. He had $180 behind at the start of the hand. The BB was also a tight, passive, and unremarkable player. He had about $450 behind at the start of the hand.

As for me, I was playing tight and aggressively and had both opponents covered. Generally, my style of play is much like Ed Miller recommends in his various books if you are familiar with his writings.

Preflop, everyone folded to me, and I opened for $12 in the HJ+1 with A 6. Both blinds were the only callers.

Flop [$36]: K 8 5.

SB checked; BB bet $20.

Normally, I would raise here with the nut flush draw, an overcard, position, and the pre-flop betting lead. However, I decided to just flat for several reasons. First, the BB likely has at least a K and probably isn't folding to a raise. Second, SB hasn't acted yet, and given his nitty style of play, he has lots of Ks in his range and could very well be holding AK or KQ (along with 88 and 55, too), hands that would never fold to a raise, either. Finally, both players were relatively deepstacked. Thus, I decided to flat the $20 because I felt I had little fold equity and was not ready yet to play for a huge pot.

The SB thought a little and it appeared as if he were contemplating a raise. However, he ultimately just called.

Turn [$96]: Q for a K 8 5 Q board.

SB checked again; BB bet $20 once again.

I hated this card and the weak lead by the BB. The Q likely hit the SB. The $20 bet gave me more than enough pot odds to call, but set up a perfect pot for a SB shove in what would now be two rounds of weak betting.

How would you play the turn facing the $20 weak lead from the BB? Is call-fold to a SB shove the only viable option?

Would your decision on how to play the turn be different if the SB were a more aggressive player (i.e., one who might occasionally attack weak bets without a strong hand or be inclined to bet his draws)?

How exactly did the Q likely hit sb OTT and why are we assuming he already nutted the flop before he reacts to BB and us?

Calling flop is fine. Raising is OK too. With SB still to act I like calling better, as we love to go multiway here with our hand.

Why do you think the Q hit SB? Are you putting him exactly on KQ? I call the turn bet. Sure the small turn lead is weak, but once we flat flop I don't think we have a lot of FE on turn, especially in a multi way pot. Head's up I'd probably raise.

If SB raises, just evaluate based on sizing. If BB calls again you probably have odds to continue.

I've played with the SB many times. He is a total nit. His betting line (both preflop and on the flop) narrows his range considerably. He is terrified of being outdrawn and outkicked. Thus...

AK is unlikely after the flop because he would have raised on the flop to drive out the flush draws. Sets and a hand like AA are unlikely for the same reason.

Before the SB just flatted the flop, I'm not assuming that he has AK, but it's part of a relatively small pre-flop calling range for this player. In other words, while I was facing the BB's $20 lead on the flop, I have to be wary about raising that bet because the SB has not acted yet, AK is within his range, and I don't want to get 3-bet and raised off of my hand.

Underpairs to the king are nearly impossible because his tendency would be to assume that one of the two players who bet and called a K-high flop could beat his underpair. The only underpair that I could possibly see him calling the flop with is QQ, which itself obviously improved on the turn.

Thus, the SB likely is a holding a hand like KQ or KJ. More imaginative players might have a wider range that would include some weaker holdings and combo-draws, but that's not this particular player.

Why can't he have KT or K9? There are some spade draws available for him as well (though a lot of them do have a Q) as well as 76s. Can he have 8x hands?

For this nitty player, weaker kings are possible, but probably unlikely. His tendency would have been to fold those hands in the SB to a raise and no other callers at the time he had to act.

A straight draw like 76 is also possible. However, 76 (particularly 76 spades) is an easy call on the flop. This player hesitated about what to do when the action was on him on the flop, and he looked like he was contemplating a raise. This guy would never, ever raise a draw. It's just not how he plays.

Thus, his likely range after the flop action is relatively small and is weighted to holding a K.

Obviously, this is not an exact science, but just based upon experience in playing with him many times and his tendencies with certain sorts of holdings.

Well, if your reads hold true, then flat turn.