Mutus Nomen Dedit Cocis
The cards are laid down in a four by five matrix and various spectators just think of any pair of cards. After shuffling and laying the cards back down then having them just point out which rows they lie in, the magician can name the correct cards they were thinking of.
The principle was first described in 1769 by Gilles-Edme Guyot.
There have been other mnemonics developed over the years that accomplish the same effect.
- The Ten Duplicates in Rational Recreations, Vol. 1 written by Dr. W. Hooper (1774).
- "The Pairs Re-Paired" in Magician's Own Book (1857).
- "Mutus Nomen" in Greater Magic (1938).
- The Pairs Re-Paired in Magical Ways and Means by Al Baker (1941) reprint in The Secret Ways of Al Baker (2003)
- "Mutus Nomened" in Hugard's Magic Monthly January 1960.
- "Mutus Nomen" by Mel Bennett, page 648 in the Pallbearer's Review, Vol. 8, No. 10, august 1973.
- "MuTarot" and "MuTwo" in Omnimancy (1981), reprint in Mind, Myth and Magick by T. A. Waters (1993)
- Mutus Nomen book by Karl Fulves (1999)