Tide of War

Oracle Text

Whenever one or more creatures block, flip a coin. If you win the flip, each blocking creature is sacrificed by its controller. If you lose the flip, each blocked creature is sacrificed by its controller.

Card Rulings

12/1/2004 Tide of War’s ability triggers only once each combat and only if at least one blocker is declared. The effect does nothing to unblocked attacking creatures.
12/1/2004 Tide of War’s controller always flips the coin. This means that you want to win the flip when you’re attacking but lose the flip when you’re defending.
12/1/2004 Even if the blockers are sacrificed, any attackers that were blocked are still considered blocked.