Cast this spell only before attackers are declared.
You choose which creatures attack this turn.
You choose which creatures block this turn and how those creatures block.
10/1/2005 You choose attackers and make blocking assignments regardless of whether it’s your turn and regardless of whether the creatures are attacking you. Your choices must be legal within the normal rules for attacking and blocking.
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.