After the defender plays cards during their focus at showdown, does focus pass back to the attacker for another action window, or does it go immediately to damage calculation?

Ruling: Focus passes back to the attacker after the defender plays cards during their focus at showdown. Damage calculation only occurs when both sides pass consecutively with no chain on the stack.

Sequence:

• Attacker has focus and passes (plays no card)
• Focus passes to defender
• Defender plays cards during their focus
• Card chain resolves
• Focus passes back to attacker
• If both sides pass consecutively with no chain, damage calculation occurs

Nuances:

• Damage calculation requires both players to be "totally happy" to proceed at the current state (both passing with no chain)