When using Ride the Wind to move Yasuo to a different battlefield while already in a showdown on another battlefield, do both combats happen simultaneously, and can players react to both?

Ruling: The existing showdown must complete first before the new combat can begin. You cannot have two simultaneous combats - the active showdown continues until its combat damage step completes, then the new combat starts.

Sequence:

• The left battlefield showdown continues as the active combat
• Ride the Wind resolves and moves Yasuo to the right battlefield
• The left showdown must complete entirely (including combat damage step)
• Only after the left showdown ends does the right battlefield combat begin
• Yasuo's "When I Attack" ability triggers when the right battlefield combat starts
• You would get a point for conquering if Yasuo takes the right battlefield after that showdown resolves
• You would also get a point for holding it once it's your turn again

Nuances:

• The rule about choosing which combat resolves first only applies when multiple combats would start at the same time, not when one is already active
• If you had moved Yasuo INTO the left battlefield where combat was already happening, his "When I Attack" ability would trigger under new rules (but not in this case since you're defending there)
• Targets for abilities are chosen when adding to the chain, not when the action resolves; pending items only occur when something would be added to the chain while another ability is mid-resolution