I often get asked the question when I show this project, what is an oracle deck? What's the difference between Tarot decks and oracle decks? And which is the Tarot of the Inner Mask Oracle deck? To briefly answer the last question, the Tarot of the Inner Mask Oracle is a hybrid deck, having the structure of Tarot but contents that are all its own. To explain more deeply, I've gone into explanations of these three topics below.
Tarot Decks
First, we should start with the term Divination. Divination has been described as the quadrant of magic that is concerned with finding out things you do not know, or any process which uses magic or the supernatural to find out things you cannot possibly know.
There are many forms of Divination. The ancients looked for signs in clouds, in animal entrails. There exists Geomancy (divination with the earth), Lithomancy (divination with stones), and any Divination using cards is called Cartomancy.
Tarot is one of the most well-known forms of Cartomancy. It comes from a tradition that originated (according to Dusty White) as a game played on the silk road. To qualify as a Tarot deck, a deck should have a few things (although, as with any "rule" when we talk about in regards to Divination, there's a lot of plasticity, unique situations and particular cases that bend them). To be recognizably a Tarot deck, at least to most of those who study and use them, a deck of cards should be divided into a Major Arcana, and a Minor Arcana.
The Major Arcana tends to have around 22 cards (although there are some decks with more, or less) and it contains all the "famous" cards, cards you might have heard of like Death, the Hermit, the High Priestess, the Wheel of Fortune, all those "characters" that have appeared in pop culture, that even those who don't know anything about Tarot can recognize as coming from Tarot. There's some decks in which some of these cards have changed names (in particular the Death card gets renamed, or entirely replaced, quite often.) But more or less, the majority of the Major Arcana cards tend to appear, in some form, even if artistically reinterpreted, in a Tarot Deck.
The Minor Arcana is divided into 4 parts called suits, each with 10 "pip" cards (numbered 1-10) and 4 "court" cards (page, knight, queen, king). This part of the Tarot deck is what evolved to be our modern playing cards, the only leftover Major Arcana card usually being the Fool, who has been included in our playing cards as the Joker. In the Raider-Waite-Smith deck, these four suits are Coins, Swords, Wands, and Cups. There are many Tarot decks that use different symbols to represent these, (such as the Weird Cat Tarot which uses strawberries and grass for example) and there's some decks which refer to Coins as "Pentacles" (Raider Waite included) but more or less, there tends to be these 4 suits, and there tends to be the page/knight/queen/king at the top of each, some flexibility given.
There exist some "Majors Only" decks which only have the 22 Major Arcana cards, and there's also some decks with a *very* liberal artistic take, creating quite different meanings for some of the cards. There's definitely flexibility and leeway in what we accept as Tarot decks, both as readers, customers at the bookstore, and clients at a reading. But more or less, Tarot decks adhere to the long tradition of the Tarot, and when you buy a new Tarot deck, even one you've never opened before, you more or less know what's going to be in the box, and you tend to see cards you recognize, even if they're a quite unique take on that card, as you go through them. With Tarot cards, a student of the Tarot can bring their knowledge to any deck, and apply what they know or feel about the entire system of Tarot to whatever new deck they encounter.
If a deck strays *too* far from these general expectations, if it changes things up so much that a student of Tarot needs to do a lot of learning and practicing from scratch in order to use it, then it starts to fall into the Oracle deck territory.
Oracle Decks
Oracle decks are the wild cards, they don't have any pre-existing structure to adhere to, usually; no traditional or customary numbers of cards or structure or sections for those cards, systems of numbering or rules of use. If creating a new Tarot deck is like designing a themed chess set, creating an Oracle deck is like inventing a new game. Oracle decks can have any number of cards the creator chooses, and can have Major and Minor Arcanas, or some other form of division, but they don't have to. They can have "suits," but not necessarily. Many Oracle decks are simply numbered 1-40 (or however many cards therein). Oracle decks needn't be intended to foretell the future, or have any other divinatory purpose. Many famous decks such as "wisdom of the day" decks or "daily inspiration" decks are categorized as Oracle Decks, and these decks are designed to be pulled one card at a time, considered as a statement or message, and not to be laid out in a spread like Tarot.
Some interesting Oracle decks include Angelarium, The Empty Cup, Moon Angels, and the Rainbow Warrior deck. However, there are countless Oracle decks.
Some Oracle decks are based on a series of images, such as The Empty Cup, which includes everyday objects combined with objects referring to exploration and outer space. In this deck, the author has written the meanings of each of these objects, and about what significance these objects could have in a divinatory setting. Many Oracle decks revolve around a theme, like animals, crystals, angels, etc., in which you'll find one animal/crystal/angel on each card, and an accompanying meaning in the guidebook. Even if an Oracle deck's cards have rather simple meanings, they can still be useful in Divination. Many people like to use Oracle cards to supplement Tarot readings, especially if the meaning of a Tarot reading is a little vague or hard to understand. Pulling in an Oracle card can be like bringing in a different advisor with a drastically different perspective, or like underlining or emphasizing some word or phrase in the Tarot reading. You can also do this even during an ordinary Tarot reading or when the meaning seems clear, just to add another dimension to the reading.
There are other Oracle decks, like Angelarium, which create an entire self-contained mythos, have a unique structure for the order of the cards, have spreads appropriate to them, and have intense, in-depth meanings written for each card. Some of these Oracles can function almost like Tarot, and be used to give a full, detailed reading all on their own.
Hybrid Decks
Hybrid decks are Oracle decks that adhere strongly to some aspect of the Tarot's structure or design. In the case of the Tarot of the Inner Mask Oracle Deck, I've designed the deck with a Major and a Minor Arcana, and the Minor Arcana has 4 suits just like Tarot (however the suits don't have court cards- instead they have 12 numbered cards each). I take the lead from a deck called the Psychic Tarot Oracle Deck, which was also designed to fit within Major and Minor Arcanas, although the contents of the cards differs from there.
I found, when I was designing the Tarot of the Inner Mask, that the cards were coming to me in forms that referred to Tarot, and I couldn't get the Tarot out of my head as I generated the images. For these reasons, I consider the Inner Mask a hybrid deck, which would not have its current structure if not for Tarot, but which branches off in its own unique direction from that tradition.