Can a player take back a legal play (Ride the Wind targeting a specific battlefield) in a competitive tournament after fully executing it, passing priority, and starting the showdown, when they realize they made a tactical mistake due to forgetting about an opponent's Ahri trigger?

Ruling: No, this rewind should not have been allowed. Rewinds are for fixing illegal game states or rule violations, not for correcting legal misplays. The player made a legal play but a tactical mistake, and multiple priority passes occurred before they requested the takeback.

Sequence:

• Player cast Ride the Wind, paid runes, selected a valid target battlefield
• Player physically moved their Vi card to the battlefield
• Priority was passed multiple times
• Showdown began and Ahri trigger went on the stack
• Only then did the player realize their mistake and request a takeback

Nuances:

• New information was gained through the priority passes (opponent did not play a response like Defy, revealing they either didn't have it or chose not to use it)
• Rule 509.3 about takebacks applies only to illegal game states, not legal misplays
• At low OPL events, judges might allow such rewinds, but not at competitive Showdown-level events
• A player can take back an action immediately if they catch themselves before completing it (e.g., "Ride the Wind to Battlefield A... actually Battlefield B") as long as no information was gained