墨子生活在公元前五世纪左右,当时,中国还是一个由许多诸侯国组成的国家。其中楚国是一个大国,宋国是一个小国。当时,一个著名的工匠公输般,为楚国制造了一种称为云梯的新式兵器,这种武器又高又大,用于攻打敌国的墙门,在当时可以说是战略性武器。云梯 Mozi lived around the 5th century BC, when China was still a country made up of many vassal states. Among them, Chu is a big country and Song is a small country. At that time, a well-known artisan made an important contribution to the Chu State by creating a new type of weapon called the Ladder, which was tall and big. The wall door used to attack the enemy country was then a strategic weapon. Ladder