How to play Hex: the rules of Hex

The board and the stones

The board is made of hexagons arranged in a rhombus. In our game you can choose a 7×7, 9×9 or 11×11 board. Two opposite edges are striped red, the other two blue. Each hexagon has at most 6 neighbours; two stones of the same colour that share a side are connected. The corner hexagons touch both a red and a blue edge.

On a phone held upright the board may be turned 90 degrees so it fits larger. That is why the game never says "top" or "left"; it names colours instead: "connect the two red edges".

A move

• Red moves first, then players alternate.
• Each move puts one stone on an empty hexagon. There is no passing.
• Stones are never captured and never move; a stone stays where it is until the end of the game.
• You can place a stone on any empty hexagon; it doesn't have to touch your other stones.

Winning

Red tries to join the two red edges, Blue the two blue edges, with an unbroken chain of stones. The chain doesn't need to be straight; it can bend as much as it likes. Whoever completes their chain first wins at once, even if empty hexagons remain on the board. In the game the winning chain glows gold.

Why are there no draws?

Imagine the board completely full. Either the red stones have joined the two red edges, or the blue stones have built a wall that cuts Red off from one side to the other. That wall is exactly a blue chain joining the two blue edges. Since the only way to stop Red is to win, every game of Hex ends with a winner; this has been proven mathematically. The hexagons matter here: each hexagon shares a full side with its neighbours, so there are no neighbours that touch only at a corner and leave it unclear whether they are connected.

Bridges and edge connections

A bridge is two stones with one hexagon of space between them and two shared empty neighbours. If your opponent plays in one of those two hexagons, you play in the other and your stones are still connected. With a bridge you advance two rows in a single move and stay safely linked.

The same idea works at the edge: a stone one row in from your own edge has two edge hexagons in front of it. If your opponent takes one, you take the other, so that stone already counts as connected to the edge.

The swap rule

Red, who moves first, has a big advantage; a first stone in the centre almost wins on its own. To balance this, Blue may say "Swap" once, right after Red's first stone:

1. Red's first stone is removed.
2. A blue stone is placed on the hexagon mirrored across the board's diagonal. For example, a stone on row 2, column 5 moves to row 5, column 2. The mirror turns the red edges into the blue edges, so the stone keeps its value: the first stone now belongs to Blue.
3. It is Red's turn again.

So Red can place the first stone neither too strongly (Blue will swap) nor too weakly (Blue won't swap and Red falls behind). The swap can only happen right after the first stone, and only once.

Settings in our game

• The swap rule is off on Easy and on for Medium, Hard and Two players. When it is on, a Swap button appears on Blue's turn.
• When the computer is Blue, it swaps if Red's first stone is not on an edge.
• First move option: You, Computer or Take turns. Whoever moves first plays Red.
• The computer plays with exactly the same rules engine you do; there is no luck and no cheating.

Common mistakes

• Thinking stones can be captured: in Hex no stone is ever captured or moved.
• Thinking the chain must be straight: it can bend as much as it likes, as long as it is unbroken.
• Counting two stones that only face each other across a gap as connected: only hexagons sharing a side are connected; two empty hexagons between them make a bridge, not a connection.
• Playing elsewhere when your opponent enters your bridge: if you don't take the other hexagon at once, your link breaks.
• Asking for the swap after Red's second move: the swap is allowed only right after the first stone, and only once.
• Expecting a draw: before the board fills up, someone always joins their two edges.