For example, in the late Qing dynasty, experts devoted a great deal of attention to solving problems related to battles pitting horse against cannon. A number of books were written on even a single variation of this problem, such as how to use horse pieces to defend against an attack on the field marshal by the enemy's cannon.
例如清朝出現的「馬砲爭雄」時期，當時人專門在馬與砲的對局上動腦筋，僅僅以砲移到中間進行攻勢、對方將雙馬佈置成屏風抵擋的所謂「中砲對屏風馬」體系，就可以寫上好幾本書。