Nash equilibrium
Also: Nash, equilibrium
A set of strategies in which no player can improve their result by changing their own strategy alone. In poker it is the formal basis of unexploitable play, and the source of the push-fold charts short stacks rely on.
The concept comes from game theory rather than poker, and it applies cleanly to heads-up situations with a single decision, which is why short-stacked shove-or-fold play was solved long before postflop play. Both players' ranges are in equilibrium when neither shoving wider nor calling tighter would gain.
It is worth being precise about what equilibrium promises: not the most money, only that no opponent can beat you by adapting. Against opponents who make mistakes, deliberately leaving equilibrium wins more.
Related terms
Full glossaryFrequently asked questions
Does playing a Nash equilibrium win the most money?
No. It guarantees nobody can exploit you, but against weak opponents an exploitative strategy wins more.