Some years ago I used to make semi-bluff raises in the wrong spots simply because I had a draw. I didn’t really understand ranges and how that impacted on your fold equity.
For example let us say that it was raised by a really tight player from the UTG seat who was also weak. If their range is AA-QQ and we called with say Jh-7h then how much fold equity would we have on a flop of 10s-8c-4s with our gutshot draw and dodgy overcard? The answer is that we probably wouldn’t have any and so making semi-bluffs really only works when our opponents are going to fold or fold some of the time.
If they don’t fold then it simply isn’t a bluff at all and all you are doing is putting money into the pot with insufficient odds with an inferior hand which is hardly a recipe for success. So our opponent is folding 0% of his range because weak players will choose to go with their hand in this situation. This is especially the case with draws present because your opponent will peg you for a draw more easily than if the board was say 10-6-2 rainbow.
So it should then become clear that our fold equity is linked to our opponent’s range and also the effective stack size. Now let us give our opponent a hypothetical range of Jd-10d, 5h-5d, 10c-9h, 3s-3c, Kd-Qh, Ac-Jd and Ah-8h. Now if we bluff raised this same flop then how many of these hands would our opponent fold to a raise? The answer, if they were tight or weak-tight, is that they would probably fold all of them and so our fold equity would be around 100% or not far off.
Now obviously our opponent will not always have junk or hands that cannot withstand heat when we semi-bluff raise and look for fold equity and they will have big hands or hands that they will not lay down some of the time. Getting back to our hypothetical example we can see that if we merged the hands from the previous example where we had 0% equity with the range of hands where we had 100% equity then our fold equity will be in the 70% mark. This may be slightly less if they chose to perhaps call with one of the hands that included a ten.
However that hand would certainly fold to a second barrel. So we can see that our opponent’s range depth, along with stack depth, is what creates fold equity.
It is much easier to find our opponent with a weak hand if they have a wide range like if they say raised from position than if they had raised from the UTG seat.
In today’s modern online poker games, many players will choose to stack off with hands like AA-KK post flop and so your fold equity post flop against these hands is seriously diminished.