Card force with 10-15 cards or less

[Rev]

I learned it from Scarne on Card Tricks in a trick called Nomenclature which uses a variation. I suspect it is even older than that and RRTCM.

No doubt. It's probably as old as the hills.

For interest: the trick in RRTCM which uses this is 'A Card and A Number'. (pg.40 in the hardback edition I have). Though, it is used slightly differently here as it used to divine the thought of number as well has locate the card.