Borgstromancy

The ability to understand a complex, outlandish, or badly explained setting or system well enough to run a game based on it.

Origin: Taken, possibly unfairly, from the name of the RPG authoress Rebecca Borgstrom (also known as R. Sean Borgstrom) who is notorious for writing games with spectacularly original premises and intriguing supporting fiction that are however almost impossible to understand well enough to actually play.