One the most simple yet misunderstood concepts about betting when last to act is that when you are called you have to be good more than 50% for the bet to be profitable. This does not mean that you have to be good more than 50%. When you are CALLED you have to be good more than 50% of the time and some situations dictate that your opponent will not call you will a lesser holding. These of course are the times not to bet when last to act.
One of the other concepts that relates to this is how pot odds are determined for you and your opponent. Let us look at a pot of $100. We are last to act on the river and the action has been checked to us. We decide to bet $50. We are risking $50 to win how much? A lot of people get confused and say $100 or $150. They do not understand that the money in the pot actually is not included in this question as we could just check back the river and win the $100. We in fact are risking $50 to win $50, which is why when we bet we have to be good more than 50% of the time WHEN CALLED in order for the bet to be profitable. Look at last action on the river as betting into a dry side pot. Any money that you are risking is only getting 1:1 odds. On the flip side of this however, our opponent is getting pot odds when he determines whether or not to call. If we bet $50 into a $100 pot he is faced with a decision of a $50 call to win $150 or 3:1. He only needs to be good here 1 out of 4 or 25% of the time to make it a profitable call. So you, as the last position better, is only getting 1:1 on a bet on the river yet your opponent is getting full pot odds. Can you see how we can actually make some really thin bets when last to act because of the pot odds that our opponent will be laid?
I played a hand at the Bicycle Casino last week that is a perfect example of this concept. We were playing $5-$10 with a mandatory $20 straddle when I picked up 88 from the highjack and raised to $80 with a $3000 stack. A very tight, Asian lady called me on the button with $2k, and a semi active, older but aware, live pro three-bet to $320 in the big blind covering me. At the time I was really on the fence as to what to do. I thought that it was such a good spot to three-bet light, because as long as the BB could get through me the lady is rarely ever calling headsup. I also knew that the live pro was capable of three-betting light but thought that if I four-bet got it in I would be doing really bad against his calling-off range. He would also fold out all of his bluffs. I thought, then with position, that my hand was too strong to fold and getting just over 12-1 on the reraise sizing (240 more to win $3000) decided to call. Surprisingly, the lady also called behind me. Pot $975. The flop came out Q♣ T♠ 8♥ and I was loving life. The BB thought for a while and bombed out $740. I noticed that the lady behind me had very little interest in the hand. Now, I am usually not an advocate of slowplaying or trapping in live cash games but sometimes when the SPR (stack to pot ratio) is low you do not really need to build a pot up with a raise to get all of the money in by the river. By calling, you sometimes can make your hand look weaker than it actually is and get people to continue on with lesser holdings. If I raise that particular board against a competent player—especially in a multiway spot—a lot of players would find a fold with KK or even AA. I did not want to give my opponent that opportunity so I decided to just call. The lady did fold behind me and the pot was now $2455 and I had a $1940 left in my stack. The turn was a 9, bringing a backdoor club draw and my opponent took a long time and checked. I decided that it was very, very difficult for me to get value from one pair hands on this board and decided to check it back and continue to make it look like I was holding on with just a queen. The 4♣ fell on the river completing a backdoor flush. The BB thought for a bit and bet $1400. Obviously, I was never folding as my hand was very under represented. I was slightly afraid of a backdoor flush but in reality unless he checked a straight on the turn there really only was A♣ K♣ as a combination or possibly A♣ X♣ if he was getting frisky with me preflop. The pot was $3855, $1400 for me to call. However, as I realized at the time, what if I was to shove? My opponent would be getting absurd pot odds—$5795, $540 to call. Over 10-1. I figured that even if he was making a very thin value bet with AA or KK trying to get looked up by AQ or KQ it would still be difficult for him to fold because he got himself so pot committed. I did ended up shoving, he called, and I was good.
This is great example of how being short at the river was a huge advantage for me. If I had had say $3000 at the end facing a $1400 bet, I probably would not have shoved versus a good player because when I am called I would not be good more than 50% of the time. But here, because I am so short he MUST call with a wider range of hands because his price from the pot is so much better. However, I am still only getting 1:1 on the extra $540, like I was betting into a dry side pot. I could have just called, just like you can check behind on the river and go to showdown.
This concept also teaches us a lesson in river valuebet sizing. Often times, but not always, the more money that goes into a pot the stronger the showdown hands will be. So you will get into situations on the river where bigger bets will only be called by perceived strong holdings. I played a hand at the Bike during the WSOPc that was a perfect example this. We were playing $5-$10 uncapped and there was a bad player that constantly kept open limping from late position. I was in a great spot as I was to his immediate left. In this particular hand he open limped from the cutoff and I raised to $40 with A♥ 9♥. Everyone folded and he called. The flop came out T♥ 8♣ 3♥. He checked and I bet $60, he quickly called. The turn was the 4♠, he checked and I double barreled for $175. He called after a long time of deliberation. The river was the 9♠ and he checked once again. For most people this would be an automatic check back. It looks like this guy has a T or a busted draw and we have picked up a ton of showdown value against that range. However, what if we were able to bet an amount that when called we were still good more than 50%? Then valuebetting would be correct, right? Of course. I figured that the guy did have a fair amount of Ts in his range but also thought that he looked at me as an aggro kid and that he might call me down light with a hand like J9, A8, 87, etc. But I wanted to size my bet where he would definitely call with those hands and I wanted to avoid getting into a situation where he would only call with a T. I decided to bet $125 giving him pot odds of $685-$125 or 6.5-1. He called pretty quickly and I was good.
You have to be careful, in these situations, however, with the amount that you bet. Let us say that when I bet over $300 he ONLY calls me with a T or better. Than betting that large amount is obviously not correct. River valuebet sizing is all about finding that sweet spot where when you are called you are good more than 50% of the time. And in a lot of situations this directly related to the pot odds that your opponents are getting laid. For a more in depth discussion of this you can check out the Seat Open Podcast episodes 11 and 12 “River Value Bet Sizing.”