Hex

Hex is the connection game invented in 1942 by Danish mathematician Piet Hein and independently rediscovered by John Nash. Two players alternate placing stones on a hexagonal grid; first to connect their two opposite sides wins. Hex has perfect information, no draws possible, and a proven first-player win (in theory, by strategy stealing). Despite this, Hex is one of the deepest 2-player strategy games — taught in computer science as a benchmark for game tree search algorithms.

How to play

• Rhombus-shaped board of hexagons (11×11 is the classic size). Here you can pick 7×7, 9×9, 11×11 or 13×13, and play against the CPU or with a friend on the same screen.
• Two players: Red owns top and bottom edges; Blue owns left and right edges.
• Red moves first, then players alternate placing a stone of their color on any empty hex. Against the CPU you play Red and the CPU plays Blue. Undo takes back the last move (in vs CPU mode, your move and the CPU’s reply).
• First player to form a connected chain from one of their edges to the opposite edge wins.
• Diagonal/hex adjacency: each hex has 6 neighbors.
• No captures, no movement. Stones stay put.

Beginner strategy

• Centre control. Centre stones connect more efficiently across the board.
• Connect immediately threatened groups. Don’t leave isolated stones.
• Block opponent’s chain. Place stones along their projected path.
• Bridge formations. Two stones connected by a “virtual” connection (two empty hexes between them) form a “bridge”: if your opponent plays in one of the two gaps, you play in the other and stay connected.
• Don’t crawl along the edge. Stones on the first row are easy to block; play a few rows out and rely on edge templates to reach your edge.

Intermediate strategy

• Virtual connections. Patterns like bridges (2 stones with 2 empty hexes between) are guaranteed connections. Identify them.
• Templates. Specific stone configurations along the edge guarantee connection. Memorize templates.
• The “edge templates.” Standardized patterns for connecting to your edge.
• Threats and counter-threats. Each move creates a connection threat. Plan threats opponent must answer.
• Avoid weak structures. Stones that can be cut from your main chain.

Advanced strategy

• Strategy stealing proof. John Nash proved first player wins. Suppose Blue had a winning strategy — Red plays any first move, then plays Blue’s strategy (extra stone never hurts). Contradiction.
• 11×11 is unsolved. While theoretically a first-player win, the actual winning strategy is unknown.
• Computer Hex. Programs like MoHex use Monte Carlo Tree Search and are among the strongest Hex players.
• Pie rule (swap). Tournaments often use a “pie rule” (not used in this version) — after first move, the second player can either play or swap colors. Equalizes first-player advantage.

Hex history

• 1942 — Piet Hein creates “Polygon” (later renamed Hex).
• 1948 — John Nash independently invents the same game at Princeton.
• Late 1940s — the game spreads among Princeton mathematicians, who call it “Nash”.
• 1952 — Parker Brothers publishes Hex commercially.
• 1990s — computer Hex research: standard CS game search benchmark.
• 2000s-2010s — Monte Carlo programs such as MoHex dominate computer Hex tournaments.

Common mistakes

• Not using bridges. Bridges are guaranteed connections — use them.
• Ignoring edge templates. Standard edge patterns secure connections.
• Random moves. Hex rewards strategic chain-building.
• Cutting your own chain. Bad placements can be exploited.

FAQ

• Q: Standard board size? A: 11×11 is the classic size; 13×13 and 19×19 are also played. Smaller boards (7×7, 9×9) suit faster casual games. This version offers 7×7 to 13×13.
• Q: Can the game be a draw? A: No — Hex is proven to have no draws.
• Q: Who wins? A: First player wins with optimal play (strategy stealing argument).
• Q: What’s the pie rule? A: After first move, second player can swap colors. Equalizes first-player advantage in tournaments.

For other connection games, try Gomoku, Connect Four, Reversi 6×6, or Dots and Boxes.