《韩非子·初见秦》
包围大梁数十天，就可攻克大梁；攻克大梁，就可占领魏国；占领魏国，楚、赵联合的意图就无法实现了；楚、赵联合意图无法实现，赵国就危险了；赵国危险，楚国就会犹豫不决。
围梁数旬，则梁可拔；拔梁，则魏可举；举魏，则荆、赵之意绝；荆、赵之意绝，则赵危；赵危而荆狐疑；此固以失霸王之道二矣。
Daliang can be conquered if it is besieged for dozens of days. If Daliang is conquered, the state of Wei can be occupied. If the state of Wei is occupied, the intention of the alliance between Chu and Zhao cannot be realized. If the intention of the alliance between Chu and Zhao cannot be realized, the state of Zhao will be in danger. If the state of Zhao is in danger, the state of Chu will hesitate.