Short-Stack Strategy: M-Ratio and Push or Fold

Measure the stack in blinds

Your stack means little on its own; what matters is how many big blinds it is. 1,500 chips is a deep stack at blinds of 25/50 (30 big blinds) and a crisis at 200/400 (under 4).

M-ratio, from Dan Harrington, divides your stack by the cost of one orbit: small blind plus big blind plus antes. An M of 10 means you can pay the blinds for ten orbits before you are out.

The zones

Harrington's zones: green above 20, comfortable and free to play normal poker; yellow from 10 to 20, where you need to start choosing spots; orange from 6 to 10, where moves are limited; red from 1 to 5, where you shove or fold. Below about 10 big blinds the same logic applies.

Why shove or fold

With a small stack, a raise leaves you committed anyway, and calling gives up your chance to make opponents fold. Going all in preflop wins the pot immediately whenever everyone folds, and needs only decent equity when called.

Shoving ranges widen with fewer big blinds and as fewer players are left to act. From the button with about 10 big blinds, many more hands are shoves than from under the gun.

Calling a shove

When you call, compare your equity with the pot odds. A shove from a short stack is usually a wide range, so reasonable hands can call. Use range equity to see how a hand does against a wide shoving range, and remember that tournament stage and ICM pressure can tighten your calls.

Questions

What is M-ratio in poker?

Your stack divided by the cost of one round of blinds and antes. It tells you how many orbits you can survive without playing a hand.

When should I go all in preflop?

Typically at around 10 big blinds or fewer, with a hand good enough for your position. The fewer big blinds you hold, the wider the range.