602.3.e. At high OPL, players must register a starting configuration from the card pool provided and must register the remaining contents of their card pool as their sideboard. 602.3.e.1. Players must use their registered starting configuration in the first game of each match. 602.3.e.2. Legend, Chosen Champion, and Rune deck composition must be registered as part of a player’s starting configuration. 602.3.e.3. For “best of 1” competitions, players must register three battlefields to randomly select from during the start of game procedure, including any “blank” battlefields they wish to use. 602.3.e.4. For “best of 3” competitions, players may select any battlefield from their card pool or a “blank” battlefield during the start of game procedure. 602.3.e.4.a. Players may only use a specific copy of a battlefield once per match, but may use the same named battlefield as many times as they have copies of it in their provided card pool.