Blocker effect on river

A simple example:
Villain is mostly representing either a missed flush draw or a nut hand. You can take in account the cards that block his flush draws in your own hand. There are other spots too but I think this is the most simple one. However, you should remember that if the card you're holding also makes a pair with the board, it's not really blocking villain's bluffs because he would play that pair in a different way.

Imo your example is also a pure assumption. If villian was 3 barreling, we dont know if he is playing c/r or c/c with some of fd, and with which exactly. Also we dont know if he is bluffing busted fd on river because bluffing busted fd on river is usually -EV because we block hands of opponent that fold vs our bet, and we dont block value hands.

But often it is the case that the range of villian is wider, e.g. we cbet flop, check back turn, and villian bets river. Now he could have many other floats as well, but his value range is still obvious. Imo when ranges are wider, we can simply sort our range by apsolute value strenght and defend top 1-a.

True, it is an assumption but I wanted to make it simple.

With wider ranges, I don't like to look for bluff blockers because first of all, people might have so different potential bluffing hands whereas the value range is better defined like you said in the opening post. I want to be blocking the value hands to call. If it's for some reason too rare or impossible to be blocking the value hands well, then I'd sort my range and call with the top portion. If my whole range is just bluff catchers, the absolute hand strength doesn't matter at all (except if villain could be bluffing with hands that are better than some but worse than some of my range) but blocking obviously matters.

If the value range is really wide too, then I think it's better to call with the top percentage. Wide value range also leaves us with the option to bluff raise if we can represent anything and there the blocking hands with bad absolute hand strength become good.

i think you made some language errors and some conceptual errors in your OP, maybe you should check it through.

conceptual questions:
a) are you assuming villain range and our hand is such that villains range is polarized to bluffs that are all worse than our hand and valuebets that are all better than our hand?

anyway, yes, blockers to bluffs can be extremely important. e.g. if 99 (bluffcatcher) on 873r 2 K can greatly reduce the busted draws in villain range

and the other guy's example is fine. there are a lot of spots in NLHE where villain bluffing range is mainly busted A high flushdraws and holding the ace of that suite yourself can sometimes reduce the potential bluffs in villain's range by about 50%

a) are you assuming villain range and our hand is such that villains range is polarized to bluffs that are all worse than our hand and valuebets that are all better than our hand?

No I am not assuming that. The only assumption is that villian bets value hands that have > 50% equity vs hero's range, and the number of bluffs is chosen such that it is unexploitable range.

and the other guy's example is fine. there are a lot of spots in NLHE where villain bluffing range is mainly busted A high flushdraws and holding the ace of that suite yourself can sometimes reduce the potential bluffs in villain's range by about 50%

Yes, exactly thats the problem, and my question. We are actually by the way just making assumption about villians bluff range (value range is more or less obvious).

E.g. Board is Kh Th 8s 3c 2s
CO opens, Hero calls from BU.

CO bets flop, turn and river, what is hero defending on river? Villian will likely value bet AK+ which is obvious for a good reg,
but we are not very sure what he is going to bluff. He can bluff mostly busted fd, in which case calling a heart makes bluff catcher horribly, but he can mostly bluff GS in which case calling KQ, KJ is bad. So if he really bluffs hands like JQ, AJ, Q9, J9, then 87s is going to be a much better bluff catch than KQ.

So thats exactly the problem and my question. Different assumptions about villians bluff range is going to change hero's calling range a lot. And thats why as a solution to this problem, I asked if it would make sense to ignore blocking bluff range, but only observe which hands block good value combos.