Description

Quadrex is a drawless connection game for two players: Black and White. It's played on the intersections (points) of an initially empty square board. The suggested board size is 19x19. The top and bottom edges of the board are colored black; the left and right edges are colored white.

A potential impasse is a 2x2 set of points consisting of two diagonally adjacent stones of one color, one stone of the other color and an empty point.

To fix a potential impasse is to place a stone of the apropriate color on its empty point so that the 2x2 set of points now contains three stones of one color and one stone of the other.

Black plays first, then turns alternate. On your turn, you must place a stone of your color on an empty point and fix all resulting potential impasses. If this creates further potential impasses, you must fix them as well, and so on.

The game is won by the player who completes a chain of orthogonally adjacent stones of their color touching the two opposite board edges of their color. Draws are not possible.

The pie rule is used in order to make the game fair. This means that White will have the option, on their first turn only, to change sides instead of making a regular move.