The Complete Rules of Quoridor

Quoridor is played on a nine-by-nine grid of squares — 81 cells, edge to edge. The two-player game is the standard form: each player controls a single pawn and starts with ten walls. A four-player variant uses the same board and the same rules with two more pawns added, one on each remaining edge, and every player's wall supply cut to five instead of ten, since there are now four supplies drawing on the same board instead of two.

Setup

Each pawn starts on the middle square of its own baseline — the edge of the board that belongs to that player. In the two-player game, one pawn begins on the middle of the north edge and the other on the middle of the south edge, facing each other across the full width of the board. In the four-player game the other two pawns begin on the middle of the west and east edges. Every wall a player will ever place over the course of the game comes from that starting supply; there is no way to gain more walls once play begins, and no way to give walls away or trade them.

The objective

Each pawn has a single goal: reach any square on the opposite edge of the board from where it started. It does not matter which square — the whole far row or column counts as the finish line, not one particular cell. The first pawn to arrive on its own goal edge wins immediately, regardless of where any other pawn is or how many walls anyone has left.

Turns

Players alternate turns, and each turn is exactly one action: either move your pawn, or place a wall. You cannot do both in the same turn, and you cannot pass — there is no "do nothing" move available to you, so if it is your turn you must either step or build. This is the whole tension of the game in one sentence: every turn you spend building an obstacle is a turn you are not spending covering ground, and vice versa.

Moving your pawn

On a normal turn, a pawn moves one square — north, south, east, or west, never diagonally — into an adjacent empty square that is not cut off by a wall. There is no requirement to move toward your goal; you may step sideways or backward if that is useful, though it rarely is, since it costs you a turn without shortening your path.

The jump

The one exception to "one square, no diagonals" is what happens when an opponent's pawn is directly in your way. If your pawn is orthogonally adjacent to an opponent's, you may jump straight over it and land on the square immediately beyond, provided that square is open. This is not an optional special move so much as what "stepping into an occupied square" resolves to.

The straight jump can itself be blocked — by a wall behind the opponent's pawn, or by the edge of the board. When that happens, you jump diagonally instead, landing in one of the two squares to either side of the opponent's pawn rather than directly behind it. You cannot choose the diagonal jump when the straight jump is open; it is only available as a fallback. This detail matters more than it looks in play: two pawns converging in the same corridor are not simply stuck queuing behind one another, and it is the detail new players most often forget to check when deciding whether a wall really seals a passage.

In the four-player game there is a third way the straight jump can be blocked: a third pawn already standing on the landing square behind the opponent you are jumping. The same fallback applies — you jump diagonally around it instead. This case cannot arise in the two-player game, since there is no third pawn to occupy that square.

Placing walls

A wall is a rigid piece that always spans two squares at once — it blocks two adjacent edges together, never one alone. Walls sit in the grooves between rows and columns rather than on top of a square, so a wall's position is described by which gap it occupies, not by a cell coordinate.

Three restrictions govern where a wall can go. First, a wall cannot overlap one already on the board — you cannot place a second wall that shares any part of the same groove as an existing one, whether it would extend an existing wall in a straight line or simply land across the same two-square span. Second, a wall cannot cross another wall running the other direction — two walls cannot occupy the same center point at right angles to each other, because a real wall piece cannot pass through another one. Walls running in different directions are free to touch corner-to-corner, forming an L or a T shape; they simply cannot cross through the same point. Third — and this is the rule the whole game depends on — a wall cannot be placed if it would leave any player with absolutely no path left to their goal.

The rule that holds the game together

That third restriction is worth dwelling on, because it is what separates Quoridor from a game where the first player to move just builds a box around the second. You are always allowed to make an opponent's route longer. You are never allowed to make it disappear. Before a wall is placed, there must still be some sequence of orthogonal steps — around other walls, using jumps where relevant — that gets every single pawn on the board to its own goal. If a wall would remove the last such route for anyone, that wall is not a legal move, even if it is your last wall and even if it would otherwise win you the game outright.

This is what turns Quoridor from a building game into a racing game. Walls delay; they do not imprison. The skill in the game is almost entirely about spending a limited supply of delay in the places where it costs your opponent the most distance for the least distance of your own.

Running out of walls

There is no rule requiring you to place a wall, and no penalty for holding some in reserve for the whole game. But once you have placed all of your walls, wall placement is no longer available to you on your turn — you can only move your pawn from then on. Running out of walls is not an elimination or an automatic disadvantage by itself; plenty of games are won by the player who ran out first, because they spent their last wall at the moment it mattered most.

Winning

The game ends the instant any pawn reaches any square on its goal edge. Because walls only ever lengthen a path and never remove it, a legal position always has at least one route open to every player still in the game — it cannot lock up in a state where nobody can ever win.

Variations

The clearest variation from the standard two-player game is the four-player form described above: four pawns starting from all four edges, five walls each instead of ten, still resolved as a single race rather than as two teams of two. Diagonal corners do not share a win condition here — each pawn plays for itself, and nobody's finish depends on a partner. Play does stop the moment the first pawn reaches its goal; nobody keeps moving after that. But the game still has a real second, third, and fourth place — once the winner is decided, the rest of the standings are read off from who was closest to finishing at that moment, rather than settled by continued play. Some casual rule sets pair diagonal players as teammates with a shared win condition; that is not how the four-player game works here.

The other common variation among casual and online implementations is board size — a smaller grid for a faster game, or a larger one for a slower, more tactical one. Standard play, including every ranked and casual quick match, uses the traditional nine-by-nine board with ten walls per player. Custom games and the position designer additionally support smaller and larger boards, for players who want a shorter opening or more room to maneuver.

For a first-game walkthrough that puts these rules into practice, see How to Play. For the ideas that separate a strong move from a weak one, see Strategy, and for quick definitions of terms like "cage" and "wall economy," see the Glossary.