Cheapest priced copy (Commander 2011): $1.49 at Card Kingdom, near mint, their price list as of .
Master Warcraft 
Instant · Rare · Ravnica: City of Guilds · #250
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.
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
5 printings · $1.49 to $24.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander Anthology | 202 | Rare | $1.99 | — |
| Commander 2011 | 209 | Rare | $1.49 | — |
| Commander Legends | 447 | Rare | $1.49 | — |
| GRN Guild Kit | 92 | Rare | $1.79 | — |
| Ravnica: City of Guilds | 250 | Rare | $1.79 | $24.99 |
4 rulings from Wizards of the Coast
- 1 October 2005You 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 January 2006You can decide that a creature won't block.
- 1 April 2008If 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.
- 20 September 2013If 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.