GRIDCHESS is a successful prototypical realization of a twofold distributed game-tree search approach where (1) a Young Brothers Wait Concept (YBWC) parallelized chess program running on a cluster forms a base component, and (2) Optimistic Pondering performs a second parallel approach on top of several clusters which can be used to achieve a further speedup. Since Optimistic Pondering is otherwise independent from YBWC, we show how the total playing strength increase is estimated for their combination by adding the isolatedly measured playing strengths for both methods. The basic ideas behind GRIDCHESS will be presented and selfplay results based on a representative mix of 35 typical openings are used to illustrate the considerations.
