Chomp Strategy: Shapes That Win
Chomp has no general formula, but several shapes are fully understood. Learn them and you'll win most games against people. New here? Read the rules first.
1. Equal-armed L: lost for the mover
An L whose two arms (beyond the corner) are the same length is a loss for whoever must move: whatever you bite from one arm, the opponent mirrors on the other until you face the poison.
2. Square bars: bite the diagonal
On a square bar, eat the square one down and one right of the poison. The remainder is an equal-armed L, so you win by mirroring.
3. Two-row bars
With two rows, the winner keeps the bottom row exactly one square shorter than the top. Whenever your opponent breaks that, restore it.
4. Think backwards
Near the end, work out which small shapes are losses for the mover (a lone poison; equal L's; the two-row pattern reversed) and steer the bar into one of them.
5. When lost, bite small
If the position is lost, take one square from the far corner and give your opponent every chance to slip.
Frequently asked questions
What's the winning first move on a square bar?
Bite the square diagonally next to the poison (row 2, column 2). That leaves an L with equal arms, and from then on you copy every bite of your opponent on the other arm.
Last updated 2026-10-21