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Which hands to push against SB limp from BB heads up

by Q.

This was a very popular question from heads up players who were surprised that it was impossible to do this kind of calculation in ICMIZER. In this article I explain how to find out shoving range against single limper from big blind position.

The problem is that when we face a limp we can guess some kind of limping range, and we can also assume what part of range opponent will throw away when we shove. So that gives us a clear way to analyze expected value of push. Other option however is unclear, when we check we will face post flop. Opponent may limp tighter ranges with an idea to trap player on BB, or he/she can limp some polarized range, or he/she can be simply a recreational player and limp a very wide range because he/she doesn’t know any better.

When I thought about a way to estimate EV of check I couldn’t come up with a reasonable model. I asked about this on twoplustwo and with coffeeyay we came to idea of letting player manually estimate his/her expected value. In this update ICMIZER allows players to put their own estimations on EvCheck. What exactly does this mean? You will need to manually predict your stack change EV as a result of playing post flop against this specific opponent with his/her limping range. Now generally players should know that EV of single hand is rarely a large number of big blinds, especially not in a raised pot. So you can predict your stack change between -2 BB and +2 BB relative to start of the hand.

If you always check fold on the flop you can’t lose more than 1 BB. That is some kind of hard lower bound. Depending on your opponent range and skill, and your hand you can expect to lose much less chips, for example in cases when you hold some kind of semi powerful hand, like suited connectors. In that case it’s probably safe to assume that we will win pot at least 25% of the time, so it can’t be much worse than -0.5 BB adjustment.

Attacking limper from big blind feature is not exclusive to heads up situations in ICMIZER. You can analyze any SNG or MTT tournament and limper can be at any position, not only small blind. It just has to be a single limper. In this spots ICMIZER will calculate ICM EV instead of chip EV, which is most relevant to heads up or early phase of MTT.

Nothing is ideal when we try to run any kind of expected value calculations in poker, so there are certain flaws in this approach. Most obvious one is that it is pretty unclear what kind of EvCheck adjustment to choose. Hopefully people will provide their input and thoughts about this. My suggestion is: follow common sense and try different adjustment values to see how your prediction affects your resulting pushing range.

Here is a sample hand which shows this new EvCheck type of spot in ICMIZER:

analyzing BB vs SB limper spot in ICMIZER with EvCheck

We think that SB limps some interesting range, a lot of strong hands and a bunch of suit connectors (99+,ATs+,AJo+,KTs+,KJo+,QJ,T4s+,94s+,95o+,84s+,85o+,74s+,75o+,64s+,65o).

We predict that when we shove he/she will fold most non broadway hands when we assign his/her calling range versus our shove to 99+,ATs+,AJo+,KTs+,KJo+,QJ.

Once we hit calculate we can observe our profitable push range. When you edit check EV adjustment a resulting range satisfying min EV Diff% changes, so if you assume that you got reasonable chances post flop it makes less sense to shove some hands, and pushing range becomes tighter. If you think that post flop action will bring you loss of your big blind with high probability, you get a looser range.

UPDATE: I have prepared a video about this new spot

I would be glad to hear any comments about this update. What kind of EvCheck you would recommend for example?