MTG Salvation

In Magic: the Gathering, resources matter. Almost every spell and ability costs mana to use, which can be gathered from a number of sources. Most of these costs are fixed costs that only change through abilities that reduce the amount of mana needed, but X spells are different. They’re much more malleable and also much more confusing, but they also tend to have much more powerful and potent effects when compared to other cards.

Take Awaken The Woods as an example. This spell costs XGG to cast, along with an undefined X value. This X value can be anything, including zero, but if it is zero, then the spell won’t do anything. The spell will then create a number of green Forest Dryad tokens equal to the amount of mana spent on defining X.

However, it’s also possible to have cards with more than one X value in the cost, such as Aggressive Biomancy. So what happens here? Well, the way a spell with multiple X’s in the value works is that each value of X must be equal. If you want to spend ten mana on the X value of Aggressive Biomancy, for example, then the overall X value of the card will be five. The overall mana total, however, will still be twelve, since both instances of X are worth five mana each.

The mana value of an X spell on the stack is always equal to the mana spent on the card, but in any other zone, the mana value of X is zero, which can be a problem specifically in Cascade decks.

X Spells and Cascade

When it comes to Cascading into an X spell (or Discovering it), X is always treated as being 0. It’s not possible if the spell is being cast using either of these mechanics, to pay mana to put towards the X cost, meaning most X spells will usually just fizzle out of existence. 

However, if you’re cascading FROM an X spell, that’s different. The mana value of the spell is set while it’s on the stack, which means the value of X is taken into account. In this scenario, X isn’t treated as 0, but rather as the amount of mana paid to cast it.

How do X Spells work with cost reduction effects?

So you’ve got a Ruby Medallion on the battlefield, which reduces the cost of all Red spells by one generic mana. How does this work with X spells? Well, it’s actually pretty simple. Basically, you first declare the value of X. Once that value is declared, you simply reduce the mana spent on X by whatever the reduction is (in this case one mana), and thus essentially get access to one mana for free.