The Decan Wheel

The decan wheel is extremely helpful in visualizing the houses within the zodiac and the tarot cards that lie within them. It is a great go-to that will help you identify and memorize where the tarot cards live as well as what energies are likely to manifest within them. I printed the one below and taped it into my notebook for quick access when practicing tarot.  

Ten degrees of separation

The zodiac houses span thirty degree sections of the wheel going counterclockwise. Aries is the first house and Pisces is the twelfth. Each of the house is further subdivided into ten degree segments called decans or decanates. The Minor Arcana tarot cards (two through ten) are assigned to each decan. The two, three and four of Wands span the entire house Aries for example.

From there you can see the suits are not arranged in order. They are assigned to houses with the same element. For example all Wands correspond to fire signs. So the next order of wands can be found in Leo, then in Sagittarius.
 

Decan Wheel

Each card/decan has a co-ruling planet. Starting with the two card in Aries we have the rulerships of Mars, the Sun and then Mercury. These are considered co-rulers because Mars is the ruling planet of the entire Aries house. The wheel also indicates the elemental triangle of Fire (triplicity), and the Cardinal aspect (quadruplicity) of Aries.    

Court Cards 

The Aces and Court Cards live on the outside rim of the wheel. In the THOTH deck the Knights, Queens, and Princesses rule entire thirty degree segments. Notice they are not evenly placed over the houses. This is on purpose. It reflects the constant interaction and balance seeking between the elements.  For example the Queen of Wands is the watery part of fire and she rules the last decan of Pisces and the first two decan of Aries. That is one third of a water sign and two thirds of a fire sign. One might think that the highest order of fire, the Knight of Wands, would rule the most pure fire sign of Aries.  However such a configuration would be unbalanced, emphasizing too much fire in one place.  Therefore the knight's rulership is assigned to Sagittarius-the least pure fire sign.  I will do a segment soon on the breakdown of the card ranks and their element classifications.     

Decan Wheel with Court Cards

How the Wheel relates to Tarot 

Decan wheels vary in design in terms of what data they contain. The more advanced wheel below adds some nice features. It includes all the previous information plus house planetary rulerships and exaltation.  It is worthwhile considering these attributes when practicing tarot, they add rich detail that might not otherwise be so easily seen in a card.  Similar to the planetary aspects in astrology, we can view the cards through the lens of the ruling planets, elements and images. 

Deluxe Decan Wheel