Zener Cards

, also known as ESP Cards, are cards used in System Scans, most specifically, clairvoyance.
==Appearance==
thumb|220px|right|Zener Cards
There are five different Zener cards: a hollow circle (one curve), a Greek cross (two lines), three vertical wavy lines (or "waves"), a hollow square (four lines), and a hollow five-pointed star. There are 25 cards in a pack, five of each design.Toaru Kagaku no Railgun BD/DVD Booklet
==Principles==
The esper being tested must be able to determine what the contents of the card are correctly.
==Background==
Perceptual psychologist designed the cards in the early 1930s for experiments conducted with his colleague, parapsychologist .
In Toaru Majutsu no Index, the card's material was changed from vinyl to ABS resin, which was instituted by the United States of America in 1992 due to a trick that the fingerprints on the card made it possible to determine the card's contents. Chapter 2 Part 1
==Chronology==
===Toaru Majutsu no Index===
====Sisters Arc====
In Tsukuyomi Komoe's supplementary lessons, she gives a lecture of the history of the ESP Card to an unenthusiastic Kamijou Touma.
====Three Stories Arc====
In the anime adaptation, cards are shown on Touma's coffee table during his attempt at finishing his summer homework.
===Toaru Kagaku no Railgun===
====Level Upper Arc====
In the System Scan of the anime adaptation of Toaru Kagaku no Railgun, a clairvoyant or a telepath is being tested using the ESP Card.
==External Links==
*
==See Also==
*Blindfold Poker
*Columbus’ Egg
==References==
Category:Terminology
Category:Science
Category:Experiments and Projects