撒手锏

撒手锏

Literally means:

one's speciality

Actually means:

ones' best card; most effective measure

铜 refers to a rectangular weapon made of metal used in ancient times.

It is often used in old novels to refer to the movement of throwing this kind of weapon at the enemy at a proper time in a fight.

Figuratively it means taking the toughest and the most effective measure at the crucial momen

锏，古代用金属制成的长条形兵器。旧小说中指厮杀时，看准机会用手中的锏投掷敌手的招数。

比喻关键时刻使出最厉害、最有效的手段。