How do you play Hex?
Two players take turns placing one stone on any empty hexagon of a diamond shaped board. Red wins by linking the top and bottom edges, Blue by linking the left and right edges, with an unbroken chain of their own stones. Stones never move and are never captured.
The colored border shows which sides each player owns. Red moves first. Hold your phone upright and the board turns to stand tall, with the red edges still at the top and bottom.
What are the rules of Hex?
| Board | A diamond of hexagons: 7×7, 9×9 or 11×11. Tournaments use 11×11. |
|---|---|
| Turns | Red first, then one stone per turn on any empty cell. |
| Neighbors | Each cell touches six others. Touching stones of one color form a chain. |
| Winning | The first player to join their two opposite edges wins. |
| Draws | Impossible. One side always connects before the board fills up. |
| Swap rule | When on, Blue may take over Red's first stone instead of playing a move. |
What is the swap rule in Hex?
It balances the big first move advantage: after Red places the first stone, Blue may claim it. The stone is mirrored across the board's diagonal and turns blue, and Red moves next.
It works like cutting a cake where the other person picks a slice first, which is why it is also called the pie rule. Red has to find an opening that is neither too strong nor too weak.
How do you win at Hex?
- Take the center early. A central stone can reach every edge.
- Play bridges. Two stones that share two empty neighbors cannot be cut: if one gap is blocked, fill the other.
- Do not block right next to a stone. Adjacent blocks are easy to walk around. Block a cell or two ahead instead.
- Make every block a link. The best defensive stones also extend your own chain.
- Near an edge, use the second row. A stone on the second row is joined to the edge just like a bridge.
Who invented Hex?
Danish mathematician and poet Piet Hein invented it in 1942, and John Nash came up with it again on his own around 1948. Nash proved the first player always has a winning strategy, yet nobody knows what that strategy is on large boards.
Controls
- Place: tap or click an empty hexagon.
- Keyboard: arrow keys to pick a cell, Enter or Space to place.
- Undo: the ↶ button, U or Ctrl+Z. Against the computer it goes back to your turn.
- Swap: with the swap rule on, the button appears on Blue's first turn (S key).
The Hard computer plays thousands of imaginary games to the end and picks the move that wins most often. The winning chain glows gold, and your record against each level is saved in this browser.