顺带不负责任的给点碎金棒科普：
It has been said that one purpose of the kanabō type of weapons was to smash enemies' armor, bones and the legs of their warhorses. The art of using this cumbersome weapon, kanabō-jutsu or tetsubō-jutsu, consisted of a mastery of both balance and strength; it required great skill to recover from a miss with the heavy club, which could leave a wielder open to a counter-attack.——Wikipedia
简而言之就是碎金棒这玩意曾经可以用来砸马腿。