From the publishers:
A game designed for two teams of two. The DOUBLES CHECKERS board is an octagon, gridded with eight parallelograms per side. The size and shape of the parallelograms adjust throughout the octagon to allow total coverage of the area.
The board contains 64 shaded parallelograms. Teammates sit across from each other, with opponents to the left and right. Diagonal movement, jumping, and kinging rules of traditional checkers apply in this game. However, the octagonal shape of the board causes the crowning rows to exist to ones left and right.
Players win by capturing or blocking from movement all opponents' pieces.