Sumo GRYB is a pure strategy game for the GRYB Game System. The goal of the game is to form a GRYB spanning four branches and multiple levels. Each turn, you make two moves (one chip twice or two chips once each): Valid moves are introducing a new chip to the root node of the tree, moving a chip down a level to a node of the lower quadrangle, or moving sideways to an adjacent node on its current quadrangle. In all cases, the chip's final resting space must be unoccupied in order for it to move there. Because valid winning combinations are essentially three-dimensional, this game is not for the faint of perception. Sumo GRYB was published in the instructions for GRYB Game System 2.0.