Hex

Overview

Hex is a pure connection game. Tiny rules, no luck, no captures — and famously deep.

The board is a rhombus of hexagonal cells. One player owns the top and bottom edges, the other the left and right. On your turn you place a single stone on any empty cell, and it stays there for the rest of the game. You win the instant your stones form an unbroken chain between your two edges.

Because the cells are hexagons, each has up to six neighbours rather than four or eight, so chains bend and branch in ways a square grid does not allow.

Choose 9×9, 11×11 or 13×13. Eleven is the default and the usual competitive size; nine is quick and tactical; thirteen leaves far more room to manoeuvre.

How to play

Place one stone per turn on any empty cell. That is the entire move set.

Stones are never moved, never captured and never removed. There is nothing to take back, so every placement is a permanent commitment — and every cell you take is a cell your opponent will never have.

Which means the two players are not building independently. You are competing for the same empty space, and a stone that extends your chain while sitting on a cell they needed is doing two jobs at once.

The swap rule

Moving first in Hex is a real advantage, so the game uses the swap (or pie) rule to balance it.

After the very first stone is placed, the second player may take that move’s colour instead of replying — effectively stealing the opening if it was a good one. A swap button appears for the brief window in which the choice is available.

That turns the first move into a genuine puzzle: play something strong and it gets taken; play something weak and you have wasted your advantage. The classic answer is to open somewhere deliberately mediocre.

Against the computer this is not guesswork. The engine swaps when your opening stone lands within roughly a fifth of the board’s width of the centre. Open near an edge and it will decline; open near the middle and it will take it. That is a rule you can actually play against.

Bridges

The single most useful idea in Hex is the bridge: two of your stones positioned so that two different empty cells would each connect them.

Your opponent can only take one cell per turn. So if they block one, you take the other and the connection holds. The link is not yet made on the board, but it is guaranteed — and it cost you one move instead of two.

This is why strong Hex positions look loose rather than solid. A row of touching stones is a chain your opponent can see and plan around; a ladder of bridges is a chain they cannot cut at all.

Recognise your own bridges and leave them alone. Filling in a bridge cell yourself spends a move to gain nothing and turns a flexible link into a rigid one.

Building and blocking are the same move

In Hex there is no separate defence. Because you and your opponent need the same cells, the stone that extends your path is usually the stone that cuts theirs.

Sometimes the best move barely advances your own connection at all — it simply takes the cell their route depends on. And since a completed Hex game cannot be drawn, blocking them is winning: there is no third outcome to settle for.

Hex cannot end in a draw

Fill the board completely and exactly one player will have a connection. Always. A drawn Hex position does not exist.

It follows from the geometry: any unbroken barrier your opponent builds across your route is itself a chain joining their two edges. There is no arrangement of stones that blocks both players.

In practice games end long before the board fills, the moment a chain completes. But the property matters while you play: every cell you deny them is a cell that helps you, and there is never a defensive position to hide in.

Strategy and tips

• Play bridges, not chains. Two cells that each complete a link cannot both be taken.
• Open near an edge if you want to keep your first move — a central opening invites the swap.
• Make double threats. Create a position with two ways to connect; they can answer one.
• Take the cell they need. It counts twice, since blocking and building are the same act.
• Block early. Waiting until their chain reaches your edge is waiting too long — the cell to take is the one in the middle of their route.
• Read the whole board. Every stone is permanent, so a move on one side can decide whether a connection on the other is still possible.

Pass & Play and the computer opponent

Three AI levels. The easier ones are for learning how connections and bridges behave; stronger ones block earlier and use double threats, which is where Hex starts to bite.

Local Pass & Play hands one device between two people, and Hex suits it as well as any game here — nothing is hidden, there is no randomness, and both players are looking at exactly the same problem.

Online multiplayer against a remote opponent is available in the Android and iOS apps. The browser version plays against the computer or a friend beside you.

Controls

• Tap an empty cell to place your stone. It stays permanently.
• Take the swap from the button that appears after the opening stone, if you want it.
• Choose the board size, AI level, Pass & Play, or a visual theme from the menu.

One rule, one action, no luck and no draws. Before every stone, ask the only question Hex asks: does this make my path stronger, or theirs weaker? The good moves do both.

If you liked Hex

Lines of Action is the other connection game here — instead of linking two edges, you gather your whole army into a single connected group, and captures can backfire badly.

Disc Flip and Nine Men’s Morris are the other pure abstracts, and Kono is a race with no captures where space is the only resource.