+ // Initialize statScore to zero for the grandchildren of the current position.
+ // So statScore is shared between all grandchildren and only the first grandchild
+ // starts with statScore = 0. Later grandchildren start with the last calculated
+ // statScore of the previous grandchild. This influences the reduction rules in
+ // LMR which are based on the statScore of parent position.
+ (ss+2)->statScore = 0;
+