Two things: First quetsion. In a game like chess or checkers, is it more efficient to perform the "search" using a search function that calls itself recursively until the specified depth is reached, or is it more efficient to build an actual search tree, with nodes, pointers to sibling nodes and child nodes? It seems like a recursive search might be a little more efficent, but that building a tree would allow you to prevent restarting the search everytime it''s your turn to move, and that the tree would allow you to simply keep searching the entire time you are playing, during it''s turn, and during it''s opponents turn. I figured I would ask this question before I spend a lot of time trying to implement both methods and testing for myself, only to find that one method is way better than the other. Second question is regarding the transpositionable table and the STL. It seems like using the STL''s map template would be a good candidate for the transpositionable table. If you know how the transpositionable table and the STL''s map template, I''d love to know if you have any thoughts on that. Thanks for your help