Editing Trick deck (section)

===Marked deck===
A [[Card marking|marked deck]] uses a marking system on the back of the cards to indicate their suit and value, so that a magician can identify a card without seeing its face. The two main methods used for creating a marked deck are ''reader systems'', which hide the suit and value in the back design, or ''coded systems'', where the suit and value is indicated by a code, e.g. a mark might be placed in a certain position to indicate the number of the card, with the color or shape of the mark indicating suit.  Many marked decks are produced commercially, while some are created using card marking techniques similar to those used to cheat at gambling, e.g. by adding tiny punctures or dots.  Some magicians may even mark a card during a performance, either with a sharpened finger nail or a tool (often a ring known as a "poker ring") made specifically for that purpose.<ref>Henry Hey (ed.), ''Cyclopedia of Magic'' (1949), p. 96.</ref>