Quote:
Originally Posted by AsianNit
I'll probably have more to say later, but for now I'd suggest people think about what concepts they would include if tasked with writing a companion piece to this COTM entitled "Reasons for Checking". It should be more complicated than "check when you don't have a good reason to bet" and may help you think about betting for reasons other than value or bluffing.
To conceptualize this idea and to also distinguish between a pure value bet vs protection bet, I've found it useful to consider very specific situations and then mathematically compare the EV of a check through, a bet we make that causes a fold, and a bet we make that gets called.
CMV and others, please correct me if I'm using faulty logic in the following examples. One tricky aspect in which I think I may differ with your examples is whether to assume villain sees two cards or only one card after calling our flop bet. Obviously it makes a big difference mathematically whether we consider a low flush draw 35% equity or 17% equity. Some of us may have a much greater tendency to check back the turn in position for pot control with top pair on boards like K
5
4
8
than others, so perhaps different assumptions need to be made for players with differing levels of turn aggression.
Anyway, the first thing I did was compare EVs of the three scenarios I mentioned. One hand I looked at (found in replayer) was when I raised A
A
in CO, got called by BB holding 7
5
, flop comes T
7
2
, he checks, I bet 2/3 pot, he folds. Kind of annoying that he folds a pair in a HU pot with such low equity. The first thing I wanted to figure out was how much I prefer that he call than prefer that he fold. So I compared the three scenarios (x will represent the pot going to the flop):
1. Check through: EV = x (0.83) = 0.83x
2. Bet causes a fold: EV = x (1) = x
3. Bet gets called: EV = 0.83 (x + 2/3x) - 0.17 (2/3x) = 0.83x + 0.56x - 0.11x = 1.28x
So given a 2/3 pot bet, my preference for a call is represented by winning an additional 28% of the pot. I do best when I make a bet and get called, but both of these are better than a check through. Scenario 3 > Scenario 2 > Scenario 1.
The next thing I wanted to figure out was the cutoff point in equity between a pure value bet and protection bet for situations in which I bet 2/3 pot on the flop. I decided to put y in place of the 0.83 I had previously had and then set it up so that the EVs of scenarios 2 and 3 would be equal.
EV = x = y (x + 2/3x) - (1-y)(2/3x)
x = yx +2/3yx - 2/3x + 2/3yx
5/3x = 7/3yx
5/3=7/3y
(5/3) * (3/7) = y
y = 15/21 = 0.714
So this tells me that for any event in which I bet 2/3 pot on the flop, I am betting for pure value when I have greater than 71.4% equity, betting for protection when I have between 50% and 71.4% equity, and semi-bluffing/bluffing/value cutting myself when I have less than 50% equity. So when I have top pair vs middle pair or top pair vs pocket pairs lower than TP I'm pure value betting, but when villain has a flush draw with two low cards I do not have enough equity to desire a call with my roughly 65% equity (under the assumption that I cannot automatically expect to be able to bet the turn).
Let's say that villain had 6
5
instead of 7
5
in the previous hand. How do the scenarios look then?
1. Check through: EV = x(.66) = 0.66x
2. Bet causes a fold: EV = x(1) = x
3. Bet gets a call: EV = 0.66 (x + 2/3x) - 0.34 (2/3x) = 0.66x + 0.44x - 0.23x = 0.87x
So this example shows that even though we prefer villain to fold his flush draw, we do better when we bet and get a call than we do when we check back the flop. I think this illustrates the point of betting for equity. Scenario 2 > Scenario 3 > Scenario 1.
As far as the argument regarding terminology goes, I find it useful to distinguish between value bets and protection bets so that I can determine how much EV my betting can generate against different portions of villain's range. As a general rule of thumb, when I bet the flop I want villain to have at least a few combos in his x/c range that allow me to get pure value rather than simply protection. If I have something like middle pair good kicker and I expect villain to x/c several top pair combos, pocket pairs higher than middle pair, and high equity draws (i.e. higher than 50% against my hand) while folding bottom pair and weak equity draws, then the EV I generate from folding out his weak draws does not allow me to make up for the EV I lose when I value cut myself against most of the other hands in his range. While I do agree that thinking strictly in terms of value vs bluff can be a useful way to start out, ultimately I do find utility in breaking things down a bit further to consider the different amounts of EV generated against different plausible combos.
Essentially, I want to use a process similar to the river value bet's question of whether there are more combos in the x/c range that I beat, but here I am focused on trying to determine overall EV against villain's flop x/c range. It does become awfully complicated when we start to think about implied odds for certain combos in villain's range, how often we are able to fire turn barrels, and exactly how wide villain is calling to give us opportunities for pure value. Guessing that advanced HUDs might do pretty well at figuring out those sort of details.