新的问题出现了：对于一般的最大最小搜索，即使每一步只有很少的下法，搜索位置的数目也会随着搜索深度呈级数级增长。在大多数的中局棋形中，每步平均有十种下法，假设电脑搜索九步(程序术语称为搜索深度为九)，就要搜索十亿个位置(十的九次方)，这样极大地限制了电脑的棋力：我们总不能忍受电脑棋手一年才下一步棋。减少搜索结点的最简单的方法是减小搜索深度-new problem has arisen : the biggest smallest general search, even if only a small step in the purgation, Search position as the number will search depth grow exponentially. In most of the middle-game, every step, an average of 10 purgation, Assuming the computer search nine-step (search procedure, technically known as a depth of nine), it is necessary to search 1 billion location (10 to nine), this greatly limits the computer chess : We can not put up with the computer players will move next year. Reduce node search of the most simple way is to reduce the depth of search