Much of what makes Shadows in the Fog work, and is somewhat unusual in RPGs, is the magic system. You may be familiar with an idea of magic in which there are in effect three parts—spell, cause, effect—and the middle step is handled by a kind of synchronicity or set of coincidences. For example, you cast a spell to break someone’s leg, and the next thing you know that person gets hit by a car and has his leg broken, but you never chose the means or method. Shadows in the Fog runs on similar principles, but the “story” of how effects get worked out is generated by rapid card-play involving all players at the table. Neither the Host nor the spell-caster’s player has all that much control. In fact, nobody has much control.
Before we get to mechanics, a few general principles.
Magic draws on ill-understood, highly unpredictable forces interwoven around us
Magic seems to have a lot to do with people’s emotions, ideas, and beliefs
Magic is utterly non-mechanistic; it cannot be defined or routinized
Everybody does magic differently, and it works differently every time
All magic draws on all the magical forces, and is not terribly selective
The more magic you use, the more you can use
Nobody knows why some people can do magic and others seem unable; whatever is going on, it’s not an identifiable “gift” or “second sight” or anything like that
Magic has no respect for space, time, or rules
Put it this way. Some people do magic. There isn’t anything apparently different about them, and it’s entirely possible that anyone can learn. Everybody who does it has rules of thumb, and some people have systems, but there’s nothing to suggest that any of these are particularly more correct than any other. There is no possibility of explaining it; it’s just there. It seems to happen a lot more when lots of people are around, and more in longer-inhabited places; some people think that this is because there is crystallized history and memory around, but that’s just another unprovable theory.
Mechanically, magic in Shadows in the Fog works on an analogy between what the players do and what their characters do. What the player does is lay down Tarot cards and interpret them in a quite freeform manner. What the character does is play with some sort of key that works for her (astrology, ritual magic, Tarot, Kabbalah, psychic meditation, whatever) and somehow kind of bend the world around her, in a rather freeform way. What the other players do is lay down other Tarot cards and interpret them freely, creating a whole story that somehow or other leads up to more or less what the original player wanted. What the universe around the character does is flex in totally uncontrolled ways to lead up to more or less what the character wanted.
A few mechanical principles can be stated at once:
Every magical “incident” begins with a Trump card being played
There are no absolute restrictions on magic whatsoever
Aesthetically, it is best to make magical effects explicable by other means, however strange the explanations—coincidence, reflections off clouds, wild animals, etc.
No one has absolute determinative power over any magical action or effect
Every card played is potentially linked to every use of the same or a related card