The benefit of alpha-beta pruning lies in the fact that branches of the
search tree can be eliminated. The search time can in this way be
limited to the 'more promising' subtree, and a deeper search can be
performed in the same time. Like its predecessor, it belongs to the
branch and bound class of algorithms. The optimization reduces the
effective depth to slightly more than half that of simple minimax if the
nodes are evaluated in an optimal or near optimal order (best choice for
side on move ordered first at each node).