3bet vs shortstacks
Posted by alefito6804
Posted by
alefito6804
posted in
Low Stakes
3bet vs shortstacks
Hi guys, i was trying to figure out what 3bet % could i have against shortstacks in BW situation. I kinda suck at game-theory-math so please bear with me :D
Lets suppose that a shortie is opening a 50% range from the btn and he's 4beting 15%. His 4bet range would be 7,5. For the purpose of what im trying to calculate im assuming that he doesn't have a flatting range, he's either 4beting or folding.
He opens to 2,5bb SB folds (0,5bb) i 3bet to 7bb and he shoves to 40b.
He is risking 37,5bb to win 2.5bb + 0.5bb + 7bb + 37.5
37.5 / 47.5 = 0,79
1-a = 1 - 0.79 = 0.21
So we need to defend "only" 21% of our 3beting range
Now, against a 7,5% 4bet range we could call his shove with something like 88+ AQo+ AQs+ which is a 5,58% range. If we only need to defend 21% of our 3beting range below im calculating how much we could be our total 3bet %
5.58/ x = 0.21
5.58/0.21 = x
x = 26.5
x = total 3bet = 26.5%
Is this correct or did i do something wrong? how would this scenario change if he's not only 4beting that range but he also has a call 3bet range? If i wanted to have a cold calling range , not only a 3betting range do i still get to 3bet as much as that or we need to 3bet less?
Thanks!
Loading 3 Comments...
You're assuming he doesn't ever win when you call with those numbers! You can think of it as he's not actually risking 37.5bb when he jams, even his worst possible hands will have in the neighbourhood of 30% equity when called.
Also, if he's opening 50%, playing 4b/fold and only jamming 7.5% then you should just 3bet any 2 and print money.
Thanks for your comment, the math may be wrong, i did the same that we do when we calculate the MDF% when someone 4bets us for example. lets say that a 100bb reg opens in EP to 3bb, we 3bet him to 9bb, he 4bets to 20bb, he is risking 17bb to win 3bb+9bb+1.5bb+17.
17 / 30.5 = 0,55 , we need to defend 1-a = 1 - 0.55 = 0.45 45% our range
In the shortie example maybe its different because we are all in and he gets to materialize his equity (? im not sure if that's what you mean when you say that he is not actually risking 37,5bb when he jams.
Also my example is not really the best because as you say if he's only jamming 7,5% of his range and folding the rest he would be folding 85% to 3bets. That's why i asked how would it change if we also add him a call 3bet range.
" In the shortie example maybe its different because we are all in and he
gets to materialize his equity (? im not sure if that's what you mean
when you say that he is not actually risking 37,5bb when he jams."
Exactly. So when you call his jam he doesn't lose 37.5bb, he has x% equity in an 81bb (less rake) pot. So his EV when called is 81*x - 37.5. So for a hand that has 30% equity, he loses 13.2bb. With 30% equity he's risking 13.2bb with a shove, and wins 10bb when you fold so you need to call at least 43% of the time which would leave you 3betting around 13%.
Though 30% is probably too low for his equity, about 24% of hands have 30% equity vs 88+/AQ, so really you need to be calling more than 43%. If he wants to play jam/fold then he needs to jam 20% if he's opening 50% (you're risking 6 to win 4 so he needs to jam 4/10 of the time). Playing around a bit his worst hands in the top 20% vs 88+/AQ are going to have about 30.6% equity, so actually you can just ignore this paragraph. Note that you should almost certainly be 3bet/calling wider than 88/AQ though if he's opening 50% and jamming 20%.
Things get much more complicated if he's also calling 3bets, and I can't really give you a good answer other than he needs to defend more than 40% of his open range if he's sometimes calling because you get to realize some equity postflop. How much more than 40% is anyone's guess.
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