通过对博弈树搜索情形的深入分析,给出极小树叶结点数定理新的完整证明,指出以往证明源于对极小搜索树的认识偏差而不完备.对窗口搜索效率来源的细致分析和实验验证,则揭示出博弈树窗口搜索提高效率的首要原因是窗口位置而不是窗口大小.这一与人们的感性认知不符的定性结论,将有助于人们准确理解和运用有关博弈树搜索算法. Through thorough analysis of the game tree search, a new complete proof of the minimum tree node number theorem is given, pointing out that the previous proofs originate from incomplete understanding of the minimal search tree, and careful analysis and experiment on the source of window search efficiency Validation, revealing that the primary reason for game tree window search to improve efficiency is the window location rather than the window size, a qualitative conclusion that is inconsistent with people’s perceptual cognition will help people to accurately understand and apply the game tree search algorithm.