Play Hex Online — Connection Board Game vs AI

Hex on Arcadia

Hex is the definitive connection game — invented independently by Piet Hein (1942) and John Nash (1948). On an 11×11 rhombus of hexagons you play red and win by joining the left and right edges with an unbroken chain; the AI plays blue and races to link top to bottom. Stones never move and are never captured. Famously, a full Hex board can never be a draw.

How to Play

Players alternate placing one stone on any empty cell.
You are red: build an unbroken chain of red hexes connecting the left edge to the right edge.
The AI is blue, connecting top to bottom.
Placed stones stay forever — nothing is captured or moved.
The first player to complete their edge-to-edge connection wins. Because exactly one connection always exists on a full board, there are no draws.

Core Rules

Each hex has up to six neighbours; adjacency is what forms a connecting chain.
Red owns the two left/right edges; blue owns the two top/bottom edges. The four corners belong to both directions.
You may play any empty cell on your turn — there are no illegal placements.
Use Undo to take back your last move and the AI’s reply.
There is no passing and no draw: the board fills to exactly one winner.

Strategy

The centre is powerful — early central stones touch more potential paths in both directions.
Learn the bridge: two stones a knight’s-ish gap apart with two empty cells between them are “virtually connected” because the opponent can’t cut both.
Every move you make to connect also blocks the opponent — offence and defence are the same act.
Build toward your edges early; don’t leave the last connection to the crowded endgame.
Watch the AI’s shortest path and drop a stone that lengthens it while shortening yours.

Practical Tips

The last-played stone is outlined so you can track the AI’s threats.
When you win, the connecting chain lights up — study it to learn strong shapes.
If a position feels lost, Undo and try a more central opening.
Think in terms of “who is closer to connecting” rather than counting stones — material means nothing in Hex.

FAQ

Who invented Hex?

Hex was invented independently twice: by Danish poet-scientist Piet Hein in 1942, and by mathematician John Nash in 1948. It became a staple of game theory and recreational mathematics.

Why can Hex never end in a draw?

It is a mathematical theorem that a completely filled Hex board always contains exactly one winning connection for one of the two players — so a draw is impossible.

What is a bridge in Hex?

A bridge is two of your stones placed with two shared empty cells between them. They are virtually connected because if the opponent plays one of the two cells, you simply play the other.