“The Poison Principle” is my attempt to label one of the most important yet most overlooked aspects of set design. At a high-level, drafting is an interactive resource acquisition exercise. The entire dynamic is shaped by how much competitive demand there is for resources. The “Poison Principle” name is derived from Scars of Mirrodin drafting, where a player drafting Infect would be interested in very few cards that are useful to a Metalcraft player, and vice versa. Basically, Infect mechanic was very mechanically isolated from other major parts of the set.
In my ChannelFireball article on the topic, I wrote the following:
This leaves us with what I’ll call the “Poison Principle”: the more isolated an archetype is from the rest of your draft environment:
1) The more focused decks of that archetype need to be in order to be successful.
2) The less other decks will want to include cards of that archetype.
Note that mechanical isolation is not a binary quantity. There are varying degrees along the spectrum of mechanical isolation, and at the far end of such spectrum lie things like Storm and Infect.
One biproduct of high degrees of mechanical isolation is that the decks in your draft environment will look very similar from draft to draft. In Scars of Mirrodin for example, almost all of the decks were members of a very small handful of archetypes. By comparison, certain cubes will allow the player to draft a huge number of playable color combinations and archetypes.
Another consequence of extreme mechanical isolation is reduced choice during drafting. If an overwhelmingly large percentage of cards are not at all relevant to the deck I am drafting, many draft packs will only present one or two cards that are playable in my deck.
It’s important to realize that even when Wizards have printed extreme mechanics like Storm and Infect, they have taken great care to provide some mechanical ties within their native environments. Time Spiral had Suspend, and Scars of Mirrodin had Proliferate.
In addition to thinking about mechanics, understanding the demand for cards in our environments can affect how we view color classification and set design in general. As cube designers, whenever we push new archetypes and strategies in our sets, we should judge the success of the design not only by whether the specific archetype is playable, but by how well the design integrates with the other parts of our cube.
For an applied example, see our article on introducing a recursive black aggro strategy.