X on the Stack

[netherspirit]

I've asked loads of people this over the years and have had a mixed response, so, I'd like to know - what does X count as on the stack?

For instance, I play Blaze with X=4. On the stack does Blaze's CMC count as 1 or 5?

[Gandalf_The_White_1]

I've asked loads of people this over the years and have had a mixed response, so, I'd like to know - what does X count as on the stack?

For instance, I play Blaze with X=4. On the stack does Blaze's CMC count as 1 or 5?

X on the stack is always what was payed, so if you pay 4R for Blaze it's converted mana cost on the stack will be 5 for purposes of cards like chalice, spell blast, etc.  It's only when not on the stack that X is treated as 0, so for Blaze has a converted mana cost of 1 for being revealed to cards like Dark Confident, Counterbalance etc.