《淮南子·兵略训》
如能这样，那么防守时就不易被攻破，交战时不易被打败，进攻时就容易取胜，这就是虚和实的关系道理。
先胜者，守不可攻，战不可胜，攻不可守，虚实是也。
If this is the case, then it is not easy to be breached when defending, it is not easy to be defeated when fighting, and it is easy to win when attacking. This is the principle of the relationship between falsehood and reality.