What's the cmc of X if I have a cost reducer?

Asked by Nereid 6 years ago

For example, if I have The Immortal Sun and I cast Endless One and tapped 6 Wastes to cast it, what is Endless One's cmc on the stack? I want to know if that's enough to trigger Sanctum of Ugin.

Jtegg007 says... #1

I'm gunna go with 7 & yes, but you may want to wait for someone to quote the rules.

I'm basing my statement off of my understanding that you don't play Endless One and then figure out what X is based on what you paid. You decide what X is going to be, then pay the required cost. (This misconception seems to be the source of many confusions when it comes to variable costs.)

February 5, 2018 7:02 p.m.

Tyrant-Thanatos says... Accepted answer #2

Cost Reduction is covered in 601.2f

601.2f The player determines the total cost of the spell. Usually this is just the mana cost. Some spells have additional or alternative costs. Some effects may increase or reduce the cost to pay, or may provide other alternative costs. Costs may include paying mana, tapping permanents, sacrificing permanents, discarding cards, and so on. The total cost is the mana cost or alternative cost (as determined in rule 601.2b), plus all additional costs and cost increases, and minus all cost reductions. If multiple cost reductions apply, the player may apply them in any order. If the mana component of the total cost is reduced to nothing by cost reduction effects, it is considered to be 0. It cant be reduced to less than 0. Once the total cost is determined, any effects that directly affect the total cost are applied. Then the resulting total cost becomes locked in. If effects would change the total cost after this time, they have no effect.

202.3d covers Converted Mana Costs with X in them.

202.3d When calculating the converted mana cost of an object with an X in its mana cost, X is treated as 0 while the object is not on the stack, and X is treated as the number chosen for it while the object is on the stack.

Essentially, cost reduction effects affect the Total Cost to cast the spell, but not the Converted Mana Cost.

February 5, 2018 7:49 p.m.

Nereid says... #3

Got it, thank you both!

February 5, 2018 8:01 p.m.

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