Another hand from 25K WSOP video, 5-handed final table, blinds 150K/300K 300K BBante UTG/HJ 9.6M, CO 16.3M, BTN 6.6M SB 6.0M, BB 6.6M. Spencer in CO moves allin with KJo and O'Donnell in SB calls with AQs.

I realize you can put a lot of ICM pressure with the stacks close, but the 22xBB also risks CO's chip lead. Why not just r/f this hand? I might shove a hand which I would have a close decision with against a 3!, but this hand would be an easy fold. Are they that afraid to see a flop? Presumably the big stack would have an advantage of being able to apply pressure postflop.

The jam is for the ICM pressure (especially with how close the three stacks behind are) and having good blockers to jam with. Everyone behind is supposed to call pretty tight on 20-22BB.

You can fold out hands as good KQ and AJ by jamming, as well as smaller pairs you'd be flipping with but would have to fold to a re-shove, let alone weaker Ax hands that might take the opportunity to reshove. Basically, you have a strong enough hand that it's not a disaster if you get called, but all the stacks behind you have strong fold equity to reshove, and you want to take that play away from them.

Whether or not it's the optimal play, I'm not sure. But the reasoning behind shoving vs. opening here is sound, I think.

I looked up the tourney in question to get prize pool numbers. I had to fudge the ante-- these ICM calculators don't let you use BB ante-- but as you can see, CO can shove profitably pretty wide, and everyone behind has to call pretty tight. (BT and SB should be at 99+, AJs+, AQo+; BB can call with 88+, ATs+, AJo. And that's assuming CO is shoving this wide and they know that.)

Nicely said!

I will add this...take a look at the five remaining players. Isaac Haxton, Darren Elias, Roman Hrabec. All big name pros. I believe O'Donnell and Spencer may be online pros.

Spencer realizes that everyone behind him has to call super tight vs an open shove here. He's getting hands to fold that have good equity against him but which may cause a headache for Spencer if they 3! him or flat called him. He's getting better hands to fold, like KQ and AJ. He's getting smaller pairs to fold to which he'd have to probably fold vs a 3! shove and is denying them to realize their full equity by open shoving himself.

Yes it's high variance when he does get called like in this instance, but Math pointed out all the reasons why open shoving KJo here is a viable play.