Quoridor

Goal: Be the first to reach the opposite side of the board!

Movement Rules

On your turn, choose one of these actions:

• Move – Move your pawn one square orthogonally (up, down, left, or right)
• Place Wall – Place a wall to block passage between two adjacent squares

Movement Details:

• You cannot move through walls
• If an adjacent square has another player's pawn, you may jump over them (if the space behind is empty)
• If you cannot jump straight (wall behind), you may move diagonally sideways to either side of that pawn instead

Wall Rules

Each player starts with a limited number of walls:

• 2-Player Mode: 10 walls each
• 4-Player Mode: 5 walls each

A wall occupies 2 adjacent segments and blocks all passage through that gap.

Important Rule: You cannot place a wall that completely blocks any player from reaching their goal. The game automatically prevents illegal placements.

Winning Condition

Move your pawn to the opposite edge of the board to win:

• 2-Player Mode:
• • Player 1 (You): Starts at the bottom, reaches the top edge
  • Player 2 (AI): Starts at the top, reaches the bottom edge
• 4-Player Mode:
• • Player 1 (You): Starts at the bottom, reaches the top
  • Player 2: Starts at the left, reaches the right
  • Player 3: Starts at the top, reaches the bottom
  • Player 4: Starts at the right, reaches the left

Controls

• Click Move mode, then click a highlighted valid position to move
• Click Place Wall mode, hover over a grid line to preview the wall (green = valid, red = invalid), then click once to place it
• Use Undo button to take back moves

Offensive Strategy:

• Always calculate your shortest path to goal before moving
• Use walls to lengthen opponents' paths while keeping yours short
• Place walls in the center of the board for maximum impact – edge walls are often useless
• Create a "wall corridor" that funnels opponents toward longer routes

Defensive Strategy:

• Keep at least 2-3 walls for emergency blocking late in the game
• Watch for opponent's shortest path and block key intersections
• Sometimes it's better to rush toward the goal than to waste turns placing ineffective walls
• In 4-player mode, focus on the closest threat – don't waste walls on players who are far behind

Advanced Tactics:

• The jumping rule can be used offensively – position yourself to force opponents into bad positions
• Double-wall blocks are powerful but consume resources quickly
• Balance offense and defense: too many walls left = wasted advantage; too few = no defense

Opening Strategy:

• In the first 5-6 moves, focus on advancing your pawn rather than placing walls——position is more valuable than walls early on
• Control the center column when possible, as it offers the most route flexibility
• Save your first walls for when the opponent commits to a path——early walls are often wasted
• If the opponent heads center, consider a wall near their path around turn 3-4 to force a detour

Quoridor is an award-winning abstract strategy game designed by Mirko Marchesi and published by Gigamic in 1997. It is based on the earlier game Blockade (invented by Philip Slater in 1975), and is also widely played online under the name Barricade. The name evokes the word "corridor," reflecting its path-blocking mechanics.

The game is renowned for its elegant simplicity and deep strategic complexity. Despite minimal rules, Quoridor offers rich tactical possibilities that reward both planning and adaptability.

Awards & Recognition:

• 🏆 Mensa Select Winner (1997)
• 🏆 Game of the Year Finalist (multiple countries)
• 🏆 Included in Mensa Mind Games list

This digital implementation features:

• ✅ Authentic 9×9 board with full rule compliance
• ✅ Intelligent Alpha-Beta search AI with multiple difficulty levels
• ✅ 2-player vs AI, 4-player vs AI, and hotseat modes (2 or 4 players on one device)
• ✅ Path validation ensuring fair play (no impossible situations)
• ✅ Undo support for learning and experimentation

Note: This is an unofficial, fan-made implementation for educational and entertainment purposes. It is not affiliated with or endorsed by Gigamic. For tournament play, refer to the official Gigamic ruleset.

Common Mistakes:

• Placing walls too early – Walls spent in the opening are rarely useful. Advance your pawn for the first 5-6 moves instead.
• Wasting walls at the edges – Edge walls seldom lengthen an opponent's path. Center walls are far more impactful.
• Only running, never blocking – If you never place walls, your opponent gets an easy run. A well-timed wall forces a costly detour.
• Spending all your walls – Keep at least 2-3 walls for the endgame to seal off your goal line or cut a key corridor.

Tips for Beginners:

• Before every move, mentally trace your shortest path to the goal — and your opponent's.
• Watch the opponent's shortest path and block its key intersection instead of placing random walls.
• Use the jump rule actively: a well-placed pawn can pin the opponent while you advance.