Rule evolution
Rule 509.3a
Previously numbered 509.4a, 509.5a.
Earliest archived Rules release: 2009-10-01 · 2 wording revisions · 2 renumberings
Earliest archived Rules release509.4aDetails
An ability that reads "Whenever [this creature] blocks, . . ." generally triggers only once each combat for that creature, even if it blocks multiple creatures. It triggers if the creature is declared as a blocker. It will also trigger if that creature becomes a blocker as the result of an effect, but only if it wasn't a blocking creature at that time. (See rule 509.1g.)
Wording changed509.4aDetails
An ability that reads "Whenever [this creature] blocks, . . ." generally triggers only once each combat for that creature, even if it blocks multiple creatures. It triggers if the creature is declared as a blocker. It will also trigger if that creature becomes a blocker as the result of an effect, but only if it wasn't a blocking creature at that time. (See rule 509.1g.) It won't trigger if the creature is put onto the battlefield blocking.
Renumbered
509.4a→ 509.5aDetailsPreviously
5. Turn Structure
509. Declare Blockers StepThen
5. Turn Structure
509. Declare Blockers StepAn ability that reads “Whenever [this creature] blocks, . . .” generally triggers only once each combat for that creature, even if it blocks multiple creatures. It triggers if the creature is declared as a blocker. It will also trigger if that creature becomes a blocker as the result of an effect, but only if it wasn’t a blocking creature at that time. (See rule 509.1g.) It won’t trigger if the creature is put onto the battlefield blocking.
Wording changed509.5aDetails
An ability that reads "Whenever [
thisa creature] blocks, . . ." generally triggers only once each combat for that creature, even if it blocks multiple creatures. It triggers if the creature is declared as a blocker. It will also trigger if that creature becomes a blocker as the result of an effect, but only if it wasn't a blocking creature at that time. (See rule 509.1g.) It won't trigger if the creature is put onto the battlefield blocking.Renumbered
509.5a→ 509.3aDetailsPreviously
5. Turn Structure
509. Declare Blockers StepThen
5. Turn Structure
509. Declare Blockers StepAn ability that reads “Whenever [a creature] blocks, . . .” generally triggers only once each combat for that creature, even if it blocks multiple creatures. It triggers if the creature is declared as a blocker. It will also trigger if that creature becomes a blocker as the result of an effect, but only if it wasn’t a blocking creature at that time. (See rule 509.1g.) It won’t trigger if the creature is put onto the battlefield blocking.