Tarot

Tarot (タロット) refers to a group of playing cards which were used in Europe from the mid-15th century onwards, for both games and divinatory purposes. Different variations have been created by certain people, including Aleister Crowley.

In Toaru Majutsu no Index, Tarot cards are used as the basis for certain forms of Magic, in particular that of Golden-style Magic.

Principles
A deck of Tarot cards consists of 78 cards divided into two categories, the Major Arcana of 22 trump cards and the Minor Arcana of 56 suit cards. Each of the 78 cards carries a certain set of potential meanings, symbolism and interpretations (and in some cases, misinterpretations), some of which differ between versions.

The meanings represented by the cards change depending on several factors, such as the type of spread being used, the positions of the cards in the spread, their positions in relation to another, and the orientation of the cards, either upright or reversed.

Using these factors, Tarot cards can be used for Magic in many different ways. For example, using a certain card after another can strengthen the useful symbols of the first card, or the troublesome ones, and a reversed card, though perhaps yielding troublesome symbols, could be used to take advantage of the affinities between the four elements.

Major Arcana
The Major Arcana (大アルカナ) is the first category of cards in a Tarot Deck, consisting of 22 trump cards numbered from 0 to 21. Each of the 22 Major Arcana is associated with one of the pathways connecting a sephira on the Tree of Sephirot.

In the standard Golden-style Tarot, also referred to as the GD Tarot (GDタロット), the Major Arcana tells the story of the Son of God, from birth to execution and resurrection, in order to draw on a portion of his power. Connected to the 22 paths on the Sephirot tree, they are meant to acquire a technique of entering the realm of god with a human body, miracles which can be explained by Christianity. The GD Tarot is also described as a reinterpretation using the secrets of Kabbalah in attempt to remove the original sin people are born with. Though they are intended to be used with arrangements based on the Sephiroth, it is also possible to perform a Telesma-level summoning using an alternative arrangement based on the Qliphoth, as demonstrated by Aleister Crowley.

In the Thoth Tarot (トートタロット) used by Aleister Crowley, the meaning behind the Major Arcana is different although based on the same tree. It instead starts at the birth of Christianity and follows it through to its destruction at Armageddon, and to the new Aeon arriving afterwards. In this version, the Hanged Man's meaning is different and Judgement is replaced with The Aeon. Instead of arriving at the realm of god, it is aimed at destroying the 'closed ceiling' of god's territory and bringing humanity to the next stage above it. The Thoth Tarot, which also form the core of an original grimoire of the same name, contains the essence of the Holy Guardian Angel Aiwass.

Although there is a common general order to the Major Arcana across variations of the Tarot, there are a few cards which are placed in a different order depending on the variant. One particularly disputed card is the #0, The Fool. Depending on the theory, it can be anywhere between the Magician (#1) and the World (#21) in the Major Arcana, or even at the very end after the Major Arcana, and depending on its position, the same arrangement of cards can have entirely different meanings. Gébelin and Waite placed the Fool at the start, while Levi put it between #20 and #21, and Westcott gave it the final #22 position. Aleister also placed it at the start, though he wasn't completely sure when making the Thoth Tarot.

Of the Major Arcana, only The Hanged Man (吊られた男)|Tsuraretaotoko (Hangudoman)}}, The Tower (塔)|Tō (Tawā)}} and The Aeon (永遠)|Eien (Aiōn)}}, has been seen used in Toaru Majutsu no Index as of yet, used by Leivinia Birdway, Arthur Edward Waite and Mina Mathers respectively. A combination of the Major Arcana from the Fool through to the World is apparently capable of greatly increasing the user's parameters temporarily, enabling them to execute supersonic movements.

Minor Arcana
The Minor Arcana (小アルカナ) is the second category of cards found in a Tarot deck, comprised of 56 cards divided in four suits; Cups, Swords, Wand and Coins. Each suit is comprised of 4 court cards; a King, a Queen, a Knight, and a Page, as well as number cards from Ace (1) to 10. The suits also have a specific element and color associated with them. Rather than connecting directly to a sephira like the Major Arcana, the Minor Arcana are used to produce symbolic weapons of their element.

Golden-style organizations make use of the Minor Arcana cards which have been optimized to be used as symbolic weapons that activating a spell associated with their element. Though they share the same attribute, these symbolic weapons are not all equal. The ones with greater numbers aren't necessarily stronger than the ones with lesser numbers - the number changes the power that manifests, meaning each card activates a different spell.

These cards are generally intended to be used in large-scale ceremonies rather than in battle. However by activating the cards reactively in order within an area, as though one were randomly flipping them up on a table, a "table" dyed in the attributes of a suit can be prepared for such a ceremony. With a chain of multiple cards complete, a Golden-style ceremony can be carried out to draw in Telesma and summon the power of an Archangel.

With the use of the cards, the number cards indicate the type of phenomenon which is to occur, while the court cards indicate who or what the phenomenon is to occur to, and store the Telesma which has been gathered.

Out of the suit cards, only the wind-aligned Sword cards have appeared in Toaru Majutsu no Index as of yet, used by Mark Space. Aside from the cards themselves, Leivinia Birdway makes use of the aspects of the four suits with her symbolic weapon, a wooden wand capable of changing forms from a wand to a cup, sword and disc to use elemental magic corresponding to the respective suits.

Suit of Swords
The Suit of Swords represents yellow, the wind, flow and change. It is symbolized by a yellow dagger (黄色の短剣).

Other Mentions

 * Aleister Crowley's AI, Reading Thoth 78's name is derived from the Thoth Tarot deck variation created by him, named after the Egyptian deity Thoth. 78 is the number of all the cards of the Tarot. The same Thoth Tarot is incorporated into its core, also making an original grimoire of the same name.

Background
Although Tarot did not have a prominent association with the occult originally, the work of magicians in the 18th and 19th centuries, such as and,  resulted in Tarot coming to be commonly interpreted as a means for divination and magic. During the time of the Golden Dawn, Arthur Edward Waite played a key role in the development of the cabal's own variation of Tarot, the GD Tarot. Aleister Crowley would later develop his own derivative, known as the Thoth Tarot.

Hawaii Invasion Arc
During the events in Hawaii, Leivinia Birdway made use of a deliberate misinterpretation of the Hanged Man in order to have the card take damage from a gunshot instead of her, while Mark Space made use of his Minor Arcana in battle with a member of GREMLIN.

Aleister Crowley Arc
During the events in the Windowless Building on December 11th, the recreation of Aleister Crowley's past shown to Kamijou Touma included his use of Tarot in a Qliphoth-based arrangement for a summoning before Mathers and Westcott shortly after joining the Golden Dawn. Later, in the battle with Aleister himself, the recreated Mina Mathers, an entity born as a result of the Thoth Tarot being incorporated into the parallel processing device Reading Thoth 78 and forming a grimoire of the same name, made use of the Aeon against Aiwass to buy some time for Touma.

Coronzon Arc
During the events surrounding the Crowley's Hazard invasion of the United Kingdom and the Ceremony of Mo Athair, Tarot-based grimoires created by Coronzon were used to reproduce the members of Golden Dawn as an anti-Crowley measure.

Kamijou Arc
Tarot, in particular the Fool, was referenced during the discussion between Aiwass and Anna Sprengel, and brought up by Qliphah Puzzle 545 and Dion Fortune in the Windsor pub meeting, both with regards to the situation surrounding Kamijou Touma and his doppelganger, with a comparison to the wandering #0.

Trivia

 * The individual parts of Toaru Kagaku no Railgun: Cold Game are designated after the Major Arcana, in numerical order.