Tartan is a connection game for two players: Black and White. It is played on the spaces (squares) of an initially empty square grid (board). The top and bottom edges of the board are colored black; the left and right edges are colored white. Squares at the intersection of even columns and odd rows are colored black; squares at the intersection of odd columns and even rows are colored white; all other squares are of a neutral color. On odd-sized boards, black and white squares can be swapped to obtain a different board.
A crosscut is a 2×2 area containing two diagonally adjacent black stones and two diagonally adjacent white stones.
Black plays first, then turns alternate. On your turn, place a stone of your color on an empty square or swap two opposite-colored stones that are part of the same crosscut. A swap must involve moving a stone to a square of its color.
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.
—description from the designer