When Player A plays a spell and chains En Garde to it before passing focus, can an opponent use Defy on the first spell or only on En Garde?

Question

Accepted Answer

Ruling: You can choose any spell on the chain to Defy, not just the most recent one.

Sequence:

Option 1: Defy any spell currently on the chain (including the first spell)
Option 2: Let En Garde resolve, then use the reaction window to respond to the first spell

Nuances:

Counter spells like Defy do not have to target the most recently played spell on the chain