Quadrex 2007

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

A potential impasse is a 2×2 pattern 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 its majority color on its empty point.

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

You win if there is a chain of orthogonally connected stones of your color touching the two opposite board edges of your color. Draws are not possible.

To make the game fair, White will have the option, on their first turn only, to swap sides with Black instead of making a regular move.