Sometimes of course the action on the river will be taken away from you. However, since bluffing ranges are at their widest on this street (fish love to bluff their missed draw on the river as we already saw), things don’t actually change a whole lot with calling versus betting. You just happen to be value calling now instead of value betting.
As I mentioned before, ranges are generally pretty polarized in no limit hold’em so oftentimes a one pair hand, especially top pair, can be a great bluff catcher. But whether you should bluff catch or not is very player dependent. In a vacuum against a nit for instance I would say that 9/10 times calling will be a bad idea because they are generally very tight and somewhat passive players.
However, board texture and the flow of the action are very important pieces of the puzzle as well.
Calling a river bet on this board,
is very different from calling a river bet on this one,
The river in the first example is about the worst card in the deck for us. It completes both the flush and straight draws. Conversely, it is the best card in the deck for their perceived range which includes a lot of draws. The river in the second example however is about one of the safest looking cards for us. It essentially changes nothing.
The first thing that you should look at in these spots however is your opponent’s AF.
AF stands for aggression factor and is the resulting number when betting and raising frequencies are divided by calling frequencies. I just focus on what the AF number means as it applies to their range though. Like with all other HUD stats you need to make sure that you have a reasonable sample size first however. I like to have at least 100 hands on somebody before paying much attention to this stat and more is always better of course.
From my experience this stat is a dead giveaway with many players at the micros as to whether they are even capable of bluffing the river or any street for that matter. And I should mention that I am referring to the overall AF as indicated above. You can use the individual AF by street as well but keep in mind that you will need a much bigger sample size.
AF of 1
Players with an AF of 1 or less are pretty much incapable of bluffing in my experience. I would be very hesitant to call a river bet against them in the situation above even on the safe river card. I think their value betting range is an overpair at minimum and often two pair or better.
AF of 2
Players with an AF closer to 2 are a bit different. They are still mostly betting for value but they will also bet with some worse pairs or random bluffs from time to time. I would call against them on the safe river and fold on the bad one.
AF of 3 or 4
Good players (TAGs) generally have an AF of 3 or 4. These players balance their range well and will show up with bluffs and good hands with a pretty equal frequency. This makes them difficult to play against. I would definitely call against them on the safe river. It’s pretty close on the bad river though.
AF of 5 or more
Against maniac types with an AF of 5 or more, you can of course call pretty wide here. I would look them up on both rivers and possibly with some middle pair type hands as well.
I just want to mention that when I talk about calling on the river here I am talking about a reasonable sized bet of between 50-75% of the pot. I have already talked about the smaller bets. You should call a bit lighter in those cases for sure given the price that you are getting on the pot.
If they bet pot or overbet however, it changes things quite a bit. I think overbets are often a very strong hand and I would stay away from calling them without some sort of specific dynamic in play. Pot sized bets can definitely be bluffs from time to time but I think they are for value more often than not. Remember we are not here to be a hero or massage our ego. If they are screwing around it will just be a matter of time anyways.