Master Warcraft | Magic: The Gathering
Formats Master Warcraft is Legal in
Official Oracle Text for Master Warcraft
You choose which creatures attack this turn.
You choose which creatures block this turn and how those creatures block.
Official Rulings for Master Warcraft
1/1/2006 : You can decide that a creature won't block.
4/1/2008 : If the defending player controls a planeswalker, the person who cast Master Warcraft first chooses the complete group of creatures that are going to attack. Then, for each of those creatures, the active player chooses who or what it's going to attack.
9/20/2013 : If a turn has multiple combat phases, this spell can only be cast before the beginning of the Declare Attackers Step of the first combat phase in that turn.