Short stack push-or-fold play
Below about fifteen big blinds the decision tree collapses to two branches, and that simplification is the whole advantage.
As a tournament stack falls, the range of sensible actions narrows. At a hundred big blinds a player can raise, call, three-bet, flat and float, and every one of those may be correct. At ten big blinds a standard raise commits so much of the stack that folding to a re-raise is no longer realistic, and the choice reduces to moving all in or folding. That reduction is not a loss of options. It is the last position in a tournament where the correct play can be known rather than estimated.
Why raising small stops working
Opening to two and a half big blinds from a ten big blind stack puts a quarter of the stack in before the flop while leaving too little behind to make any postflop decision meaningful. An opponent can re-raise all in with a wide range knowing that a fold surrenders a quarter of the stack. Moving all in immediately removes that leverage: there is nothing left to raise into.
What drives the shoving range
| Stack depth | Under the gun | Cutoff | Button | Small blind |
|---|---|---|---|---|
| 15 big blinds | top 8% | top 15% | top 25% | top 32% |
| 12 big blinds | top 10% | top 19% | top 31% | top 40% |
| 10 big blinds | top 12% | top 23% | top 38% | top 48% |
| 7 big blinds | top 17% | top 32% | top 50% | top 60% |
| 5 big blinds | top 24% | top 44% | top 64% | top 75% |
The table above gives rough shapes rather than exact charts. Three things move them. Stack depth widens the range as it shrinks, because the blinds are worth proportionally more. Position widens it as fewer players remain to act. And the payout structure narrows it near a pay jump, where surviving has value that the chips alone do not capture.
Calling a shove is a different question
A calling range is always tighter than a shoving range at the same depth, and the gap surprises people. Shoving wins the blinds whenever everyone folds, and that fold equity is a large part of the value. Calling has no fold equity at all: the hand has to be ahead when the cards turn over. A holding that is a comfortable shove from the button can be a clear fold facing a shove from the same seat.
Practising it away from the table
Push-or-fold is the part of tournament play that rewards rote work most directly, because the situations recur constantly and the correct answer does not depend on reading anybody. Drilling the shapes with flash cards until the decision is instant is worth more than any number of hands played without review.