bù dǎ bù xiāng shí
指经过交手,相互了解,能更好地结交、相处。
明·施耐庵《水浒传》第38回:“戴宗道:‘你两个今番却做个至交的弟兄。常言道:不打不成相识。’”
不打不相识作分句;形容经过交手而结交
It takes a fight for people to get know each other.