ㄍㄜㄐㄧㄧㄢyānㄩㄥˋyòngㄋㄧㄡˊㄉㄠniúdāo

割鸡焉用牛刀
  1. 哪裡用得著比喻處理無須動用大量人力物力不值大才小用殺雞焉用牛刀」。 割雞焉用牛刀隨便個人去處」。

lit. why use a pole-ax to slaughter a chicken? (idiom)​, fig. to waste effort on a trifling matter, also written 殺雞焉用牛刀[sha1 ji1 yan1 yong4 niu2 dao1]