Raise/Folding in LHE? ICM Tales from the Streets

A few days ago, professional poker player and limit hold’em specialist Terrence Chan posted an interesting spot from the final table of a WSOP online $2500 Limit Hold’em event.

Terrence Chan LHE FT Hand History
Terrence Chan LHE FT Hand History

The players are 7 handed, and Chan is in the LJ with 4.5bbs and JTo (in the following tweet he says he accidentally missed the open). Chan folds, and it folds around to the SB who raises. BB 3bets with 6.6bbs (2nd shortest stack) and SB folds.

Now, the questions are: 1) what is Chan’s range, should JTo be an open as it is in cEV? And 2) is there ever a legitimate reason to raise/fold to a single bet in LHE?

Before running the sims, I predicted that JTo is not in Chan’s opening range, and I also made the case that, given ICM pressure on the BB because of Chan’s short stack (which is about to hit the blinds), BB’s 3bet range is probably linear and tight, and that SB is incentivized to open very wide in this spot. And, since BB isn’t incentivized to get it in light here, and given that the SB has a substantive risk premium vs BB – since losing the pot would make the SB the short stack at the table – it makes sense to me to fold the bottom of their opening range. This is especially true if SB decided to open very wide given ICM pressure they can exert on BB.

Drkamikaze tweet: "My guess before running it is that SB can exert extreme ICM pressure on BB given their and your stack size, so raise folding bottom of a very wide range (60%+) makes sense. BB can't play back with much, 3bet should be a nutted linear range. Will run a sim tho to confirm."

Text 1: "BB has a 10.5% risk premium vs SB, but SB also has a fairly high risk premium of 7.5% vs BB. With a bigger stack I think SB could raise 80%+, and with a huge stack probably any 2." Text 2: "Not certain you want to raise the JTo anyway here. I'd probably pass. In ICM spots like this you probably want decent pairs and As and Ks mostly as well as suited broadways (so JTs but not JTo). Will be interesting to see the range when solver is done."

So, how did my predictions fare after running sims?

Let’s start with Chan’s RFI off of 4.5bbs:

HJ 4.5bb Opening Range
Terrence Chan (HJ) 4.5bb Opening Range

The range looks about like what I thought. HJ opens 55-66+, A9o+, KJo+, suited broadways and A3-A4s+. Just as in NLHE, our range favors A and K blockers, and even though Chan is very short, he still has a 5-8% risk premium vs all the other players, so this is not a spot he should open wide. So good fold! Turns out Chan saved himself a few hundred dollars worth of equity!

Next, let’s consider my hypothesis, and the strategy I would have used if I were in the SB in this spot. First we will look at the GTO ranges and strategy that the solver output:

SB RFI - GTO
SB RFI Range – GTO

In equilibrium, the solver has SB opening a very wide range. I predicted around 80%+, and I was pretty close with the GTO strategy opening 77%. In ICM, it’s a common heuristic that a covering stack opens wider than cEV vs a shorter stack that has a high risk premium, as in this case, where the BB has over a 10% risk premium vs SB. The BB can’t do much in response because they are so incentivized not to bust before Chan.

What about the BB response to the SB’s aggressive open?

BB(6.6) Strat vs SB open -GTO
BB(6.6) Strat vs SB open -GTO

I predicted a linear range, but the result was actually a polar range of our top hands and some weaker offsuit and suited combos as bluffs. But I was correct that it would be a narrow range: BB only 3bets 13% of the time, folding or flatting the rest of their range.

Versus the BB’s small, polar range, how does SB respond?

SB Strat vs BB(6.6) 3bet -GTO
SB Strat vs BB(6.6) 3bet -GTO

SB 3bets a 16% polar but fairly linear range, mostly flats, but does have a few folds at the bottom of range as predicted. T5o and 85o specifically are indifferent and fold some of the time, but also many of the hands at the bottom of range will be near 0EV, so if I thought BB was underbluffing I would fold more of the bottom of range.

Now, I have no idea about BB’s stats and play prior to this hand other than Chan’s comment that both SB and BB had played well the day before. But if I was SB, and I had info that the BB might overold to an open here, or I believed that they were unlikely to have the bluffs in the sim above in their 3bet range – or even if I thought they would just be underbluffing a bit – I would raise even wider than the GTO SB range above. In fact, if I thought they were very much too tight, I might open over 90% even.

So what would the solver do if BB was only 3betting their top of range?

SB RFI vs BB locked linear 3bet
SB RFI vs BB locked linear 3bet

Now SB GTO strategy is to open nearly 82% vs BB’s range below:

SB Locked Linear 3bet Strat
SB Locked Linear 3bet Strat

The solver doesn’t open significantly wider vs a BB who is 3betting a very tight, linear top of range, just a little bit less than 5% more. However the SB strategy in response to BB only 3betting a 7% linear range is to fold 43% of their range!

SB Response to BB Locked Linear 3bet Range
SB Response to BB Locked Linear 3bet Range

This is significantly more folding than in the first sim vs the BB polar range with bluffs. When our opponent doesn’t have the bluffs in their range, the EV of hands at the bottom of our range – in this case many – becomes negative, making it correct to fold them.

Now, I have no idea who these players are or if the situation is as I described. It may well be that there was collusion or something off going on here. But as we can see from the solver outputs, raise/folding here in the SB is a legitimate strategy.

This changes if the BB has fewer chips though. If the BB has 3.5bbs, for example, SB should only be opening hands they are willing to call off. But also, and maybe this will be surprising to some, but even with 3.5bbs the big blind has a substantial folding range. And SB isn’t even close to opening any two.

Which leads us to a fundamental strategy tip I can give to those who are not experienced with limit ICM tournament play: just because you are super short does not mean you should be stacking off light. In fact, apparently Chan came back from his 4.5bb stack here to win the tournament! Thank goodness he made the correct fold in this spot, even if inadvertently, which may well have led to that victory.