Drill PokerPicture it: the tournament bubble, you have 20 big blinds, an opponent shoves, and you look down at pocket queens. By any chart this is an easy call. In money terms it may be the worst decision of your entire tournament. To understand why the charts suddenly "break", you don't need formulas — you need one idea: tournament chips and money trade at an unfair exchange rate.
A chip is not a dollar
In cash games it's simple: a chip on the table equals money in the cage; double your stack and you've doubled your capital. Tournaments don't work that way, because prizes are paid in steps and the player who busts loses everything at once.
A thought experiment. A 10-player tournament, $100 entry, everyone starts with 1,000 chips. At that first moment your stack is "worth" exactly $100 — you haven't taken anyone's share of the pool yet. Now you double up: 2,000 chips. Are you twice as rich? No: with three places paid, your shot at first place grew, but second and third "weigh" less, and the fair price of that stack is roughly $180, not $200. Each new chip brings a little less than the one before — and the last chip you lose, elimination, is the most expensive of all.
ICM (Independent Chip Model) is simply a way of computing that exchange rate honestly: the model takes every stack at the table and the payout structure, and converts chips into expected money. From "chips get cheaper as the stack grows" follow all the tournament adjustments below.
Why the call suffers first
The main practical consequence of ICM is asymmetric: the shove barely changes, the call tightens sharply.
The pusher wins two ways — either everyone folds, or he wins the showdown. On the bubble the first way works even more often than usual: everyone is afraid to bust, and the folds come generously. The caller, though, wins only at showdown and always puts his tournament life on the line. When busting costs more than doubling gains, the caller pays more for the same hand than he stands to receive.
Hence the decisions that look strange at first sight but are the norm on the bubble:
- QQ goes into the muck against a big stack's shove when two shorter stacks sit nearby;
- shoving "junk" into a medium stack becomes more profitable than in the mid-game — calling costs him even more than shoving costs you;
- small pairs and weak aces, standard calls against a wide shove, march off into the fold column together.
Three stacks, three roles
ICM assigns players roles by stack size, and playing someone else's role is expensive.
The big stack — aggressor by appointment. Elimination doesn't threaten him, and every one of his shoves confronts opponents with "call at the price of your tournament life". Failing to apply pressure with a big stack on the bubble means declining the most profitable seat in the tournament.
The medium stack — the main casualty. He has something to lose, and everyone leans on him: the big stack with impunity, the short ones out of desperation. The medium stack's role is to endure: tight calls, careful shoves, no heroics. It is boring, and it is correct.
The short stack — the freest of all. There is almost nothing left to lose and doubling is the only path, so the short stack plays closest to the ordinary charts. One caveat: if an even shorter stack sits at the table, it can pay to outlast him — let the bubble burst on someone else.
How to train it
Reading about ICM helps, but payout-jump pressure becomes a skill only through hands. In the ICM trainer, every spot gets two verdicts — in chips and in money: when they match, the ordinary chart applies; when they diverge, you're looking at exactly the kind of hand that busts players on the bubble. The difference shows up on the 13×13 grid — along with the price of the mistake.