The word 'Hexagnosis' is derived from Prognosis. The meaning of Prognosis is 'a forecast of the likely outcome of a situation'. Hexagnosis means 'the forecast of the likely outcome of a situation which has six possible outcomes.'
The performer predicts, very cleanly and accurately, the exact choice of a participant from among six possible options. A couple of ordinary business cards and a pen is all you need to perform this cool routine.The principle is so simple and powerful that you will find yourself performing this almost every day, to any new person you may meet.
The underlying principle is extremely flexible too. A participant can make a list of any six names or personal objects or places or goals or living & dead names etc and choose any one from among these options. Your prediction of these one-in-six choices will always be spot on.
There are no sleights, no preshow, no stooges, no swami gimmick, no Unswami gimmick, no peeks, no impressions, no switches, no stacks, no tech, no math, no tearing, no instant stooging, no dual reality.

But for the couple of ordinary business cards and pen, this routine is quite impromptu and almost propless.
You will find that the potential of this simple and powerful principle is vast and the only limit for its creative usage is your own imagination.