Assassin's Mace (Chinese: 杀手锏; pinyin: Shāshǒujiàn) is a Chinese term composed of the characters for "kill", "hand", and "mace". This term has its roots in ancient Chinese folklore, which recounts how a hero wielding such a weapon managed to overcome a far more powerful adversary. "Shashou Jian" was a club with which the "assassin" incapacitated his enemy, suddenly and totally, instead of fighting him according to "the rules."
The novel Assassin's Mace by Author, Evan Pedone, discusses the use of the Assassin's Mace as a weapon which brings the world into World War 3, almost annihilating the United States dominance in the world.
The term as a figure of speech has been around for centuries and has been revived in contemporary Chinese pop culture, as a slang phrase that appears in articles about everything from soccer to romance. In popular usage, the term is roughly equivalent to the English idioms "silver bullet" or "trump card", and means anything which ensures success.