Can showdowns start after a unit moves into a battlefield, including an empty one, and are there any other circumstances that would start a showdown?

Ruling: A showdown can be triggered by moving into a battlefield controlled by your opponent or by moving into an empty battlefield. Specifically, a showdown opens when a move causes a battlefield to become contested while it has no units present from any player other than those that just moved.

Sequences: N/A

Nuances:

• The showdown occurs without combat when triggered by movement
• The battlefield must become contested as a result of the move
• Only applies when no other units are present besides those that just moved