Meet Zhuge Liang, the man who fought back a superior enemy with the help of a guqin and an open gate.
I wanted to write about this guy in my Wargaming with Gandhi post, but I couldn't for the life of me remember the details or where I read about him. Cracked.com of course, where else.
It's in all probability a fictious account, but there have been real uses of this strategy. It made its way into the Thirty-Six Stratagems book, which is a worthwhile read for gamers, wargamers and roleplayers both. Here's a copy in English and French.