Kokkuri

Kokkuri (狐狗狸) refers to a type of game or divination done in Japan.

Principles
It is unknown on how the Kokkuri is in Toaru Majutsu no Index, but it can be presumed that it uses a mechanism, which is called the Kokkuri, and has the participants ask questions, which in theory, have the "spirits" move the mechanism as an answer.

Angel Fall Arc
Tsuchimikado Motoharu references it along with Planchette as an example on how they are similar to Hino Jinsaku taking commands from the writings of his right hand.

World Rejecter Arc
Elza, a magician of the Kamisato Faction, is described as utilizing 'something like a' Kokkuri to possess people and objects, usually the coins she carries around.