Will and LED

[lilmidget]

I know that you can play a Thoughcast with 4 artifacts on the board by announcing the spell, then sacing a sphere for U mana to pay for it.

My question is, why can't you announce Yawgmoth's Will, then sac Lion's Eye Diamond to pay for it?

It seems to me that it should work the same way, but I was told a while ago that this wasn't legal. Can anyone help please? Thanks.

[Matt]

Because LED's mana ability says "Play this ability only any time you could play an instant" and you can't play instants during the announcement of spell.

The Thoughtcast example is different because Chromatic Sphere's mana ability doesn't have that extra clause.

You can play mana abilities during announcement of a spell unless otherwise stated. LED, Charmed Pendant, and Witch Engine are the only cards that currently have this clause, and Rhystic Cave has a similar but not identical clause.

Oh and [card]Mana Screw[/card] but that's Unhinged and the rules are looser there.

[lilmidget]

Oh I see. Thanks for the quick response.

[Gabethebabe]

Note that even though LED´s ability has a restriction, it is still a mana ability that can´t be responded to, doesn´t use the stack and can´t be countered.