[Spicymoose]

If he 3-bets preflop with 88+, KJs+, KQ, ATs+, AJ+, then assuming a blank river fell, we would be behind 54 combos of pretty reasonably played high cards, QQ, KK, and AA. We are ahead of 88,99,TT,JJ, which have 24 combos. For us to be ahead on the river if he bets a blank, the combos which we area ahead of have to end up being 6 (so that we win 6 outa 60, or 1 in 10). That means he to play his underpairs the way he did at least 25% of the time he has them. I don´t think this is the case, even against some pretty crazy opponents.

Therefore I think if you are calling the turn, you can still fold to a blank river.

As for calling the turn, if we assume that the higher underpairs (TT, JJ) bet about 50% of the time, and the lower ones bet maybe 25% of the time, we have 9 combos of hands that we are currently ahead of if they bet. This is assuming that these hands raised the flop, which a bunch of them didn´t. So in reality, they have even less combos of these hands. Considering we improve against some of the hands that are ahead of us sometimes, and that usually the hands that are behind us will give up, I think a turn call might be ok if you expect our opponent to be betting his underpairs this often. That is a decision of judgement though. I think there are plenty of opponents who will not ever bet these underpairs, or who will rarely do so. Against these, a turn fold is a must. If there is some significant chance that they might bet these hands, then you can call the turn, and fold the river UI.