Hex

Hex Rules

• Two players take turns placing one stone per turn.
• Red tries to connect the top edge to the bottom edge.
• Blue tries to connect the left edge to the right edge.
• Stones are never removed. You cannot pass your turn.
• The first player to complete a connected path wins. Draws are impossible.

Pie rule (optional, for fair play): after Red places the opening stone, Blue may take it — the stone moves to the reflected position and becomes Blue's. Red keeps their color and plays next. This prevents extremely strong openings and balances the first-player advantage.

A bit of history

Hex was invented twice independently. The Danish mathematician Piet Hein presented it in 1942 in the newspaper Politiken under the name Polygon. A few years later John Nash — yes, the Nash of A Beautiful Mind — rediscovered it at Princeton in 1948; the game was first known there as "Nash" or "John". The current name "Hex" comes from the version that Parker Brothers commercialised in 1952.

Nash proved one of Hex's most beautiful results with a strategy-stealing argument: on any size, the first player has a winning strategy — even though for boards larger than 9×9 we still don't know the strategy explicitly. The pie rule above is the practical answer to that mathematical truth.