Second entrance introduction: The second "Combat Chapter" discusses the importance of quick victory. Because sending troops to fight will consume a lot of manpower, material resources, and financial resources of the country. If it goes on for a long time, the army will be exhausted, its spirit will be dampened, and its wealth will be depleted. Other princes will take the opportunity to attack. Starting from the idea of ​​quick victory, Sun Wu opposed using the crude combat weapons of the time to conquer fortified cities, and also opposed the repeated recruitment of soldiers and the transportation of military supplies domestically. Instead, he advocated providing food and grass on the spot in the enemy's country, and advocated rewarding the soldiers with riches. He advocates preferential treatment of prisoners and uses capture to supplement and strengthen himself. He believed that by doing so, he could quickly defeat his enemies.