You might also like The Thoth Tarot and Your Birth Cards, about the Thoth Minor Arcana and Astrology
n.b. The Decan/Zodiac Wheel image below is designed with the Thoth deck in mind. The Thoth Court Cards are, in order from the top of the Tree down: Knight, Queen, Prince, Princess. To use it with a RWS-based deck, replace Knights with Kings; Queens stay the same; replace Princes with Knights; replace Princesses with Pages. The image just below shows where the RWS Courts reside.
Say you’re doing a Tarot reading with the Tree of Life and you get a Court Card. You draw the Knight (RWS King) of Disks. You know he belongs in the 2nd Sephira, and you know that means his energy is vast but unfocused, full of potential but still a Jack-of-all-trades-and-master-of-none.
There’s more you can find out about your Court Card to inform its situation and its relationship to the cards that come before or after. Each Court Card rules three Minor Arcana, and as you can see in the illustration, they also co-rule those three Minor Arcana with two other Court Cards. If you look at your Knight of Disks, you can see he is related to the Princess (RWS Page) of Wands and in fact the Ace of Wands. What might this inter-relationship mean in a reading? Maybe nothing, but maybe … something. It’s another layer to check out as you work through your cards. Plus, it gives you more birthday cards!
We need to talk about decans
The Zodiac Wheel is a circle, and like all circles, it measures 360 degrees. For the Zodiac Wheel, we divide it evenly into the 12 pieces where we put the Zodiac Signs. You can see this in the image. Each of the 12 Signs covers 30 degrees of the Wheel (360 / 12 = 30). You can see all of the Zodiac signs that rule their section of the Wheel.
You can also see that each Zodiac sign is itself divided up into thirds. These are the ‘decans’ which are each 10 degrees. They originally come Arabic astrology, and some divination decks use them – I love The Moon Oracle, for example, which includes cards that each represent each ‘Moon Mansion’. These cards come with interpretations, but I prefer to think for myself about what the connection might mean.
Knights, Queens, and Princes
If you look at the inner ring, at the bottom of the image, you will find the Queen of Cups in blue. You can see that she rules the 2 of Cups and the 3 of Cups, and also the 10 of Swords. Next to her, the Prince of Wands rules the 4 of Cups and the 5 of Wands and the 6 of Wands. Each Knight, Queen, and Prince rule two decans in their own sign and one decan in the next sign. I am reading this Wheel going counter-clockwise because that is the order of the Elements on the Tree of Life: Fire, Water, Air, Earth.
Princesses and Aces
The Princesses span three Signs and rule nine Minor Arcana. The Princess of Wands, at the bottom in red, rules the 2, 3, and 4 of Cups, the 5, 6, and 7 of Wands, and the 8, 9, and 10 of Disks.
The Aces are on the outer ring, and they also rule three full signs. They match the Princesses, in fact. The Aces are beginnings, at the top of the Tree of Life in Kether, and the Princesses are the end result residing at the bottom of the Tree of Life in Malkuth. The beginning and the end together – Alpha and Omega – showing the constantly moving, cycling energy on the Tree. Once you get to the bottom, you circle around and start back up. It’s like The World card: we step through the energy in Malkuth and find ourselves immediately on the path back up toward Kether.
Decans and your Birthday
Look on the chart just inside the inner ring and you’ll see a section of the wheel where the pieces all have dates. Say your birthday is 12 October. That would put you on the right side of the Wheel in Libra, with the 3 of Swords on one side and the Queen of Swords on the other. In this case, I would call the Queen of Swords your ‘birth card’, and I would look at the 3 of Swords as an energy you would have access to in this lifetime.
If you drew the Queen of Swords in a reading, you could look at the 10 of Disks, the 2 of Swords, the 3 of Swords and the energy of Libra for clues you can use. How could those cards work together in the context of the question? Do any of them stand out?
Also, one thing about all of this – just play. See where your instinct guides you. There are no hard and fast rules. If I’m doing a reading and draw the Queen of Swords and the 6 of Cups, I might look on this Wheel and see that moving from the Queen to the 6 of Cups leads me through her Swords cards, not her one earth card. So I might then think that Air was the important element. Look at the relationships on this wheel between the cards that you draw and see if something occurs to you. Maybe your cards are on opposite sides of the wheel, and maybe that tells you something important about your question.
Looking at the decan for birthday 12 October again, you can see that it is also included in the domains of the Princess of Cups and the Ace of Cups. Does that change how you see the Queen of Swords and the 3 of Swords? Does it change how you see the Queen of Swords and the movement to the 6 of Cups?
October 12th is Aleister Crowley’s birthday, which means that his ruling court card is technically the Queen of Swords. He decided to choose another one, though, and who’s going to say No to the Magic Man? He chose the Prince of Wands, which is a powerful, vibrant card that *cough* one would be very lucky indeed *cough* to have as one’s own genuine birth card *cough*.
Now find all the cards for your birthday!
These associations are important for Tarot readings and they are also really interesting for your own spiritual practice. If you look at all the cards associated with your birthday, does it help to know where your strengths are, and maybe your weaknesses, too?
 The Moon Oracle: Let the Phases of the Moon Guide Your Life by Caroline Smith and John Astrop