Rule evolution
Rule 509.3c
Previously numbered 509.4c, 509.5c.
Earliest archived Rules release: 2009-10-01 · 1 wording revision · 2 renumberings
Earliest archived Rules release509.4cDetails
An ability that reads "Whenever [this creature] becomes blocked, . . ." generally triggers only once each combat for that creature, even if it's blocked by multiple creatures. It will trigger if that creature becomes blocked by at least one creature declared as a blocker. It will also trigger if that creature becomes blocked by an effect or by a creature that's put onto the battlefield as a blocker, but only if the attacking creature was an unblocked creature at that time. (See rule 509.1h.)
Renumbered
509.4c→ 509.5cDetailsPreviously
5. Turn Structure
509. Declare Blockers StepThen
5. Turn Structure
509. Declare Blockers StepAn ability that reads “Whenever [this creature] becomes blocked, . . .” generally triggers only once each combat for that creature, even if it’s blocked by multiple creatures. It will trigger if that creature becomes blocked by at least one creature declared as a blocker. It will also trigger if that creature becomes blocked by an effect or by a creature that’s put onto the battlefield as a blocker, but only if the attacking creature was an unblocked creature at that time. (See rule 509.1h.)
Wording changed509.5cDetails
An ability that reads "Whenever [
thisa creature] becomes blocked, . . ." generally triggers only once each combat for that creature, even if it's blocked by multiple creatures. It will trigger if that creature becomes blocked by at least one creature declared as a blocker. It will also trigger if that creature becomes blocked by an effect or by a creature that's put onto the battlefield as a blocker, but only if the attacking creature was an unblocked creature at that time. (See rule 509.1h.)Renumbered
509.5c→ 509.3cDetailsPreviously
5. Turn Structure
509. Declare Blockers StepThen
5. Turn Structure
509. Declare Blockers StepAn ability that reads “Whenever [a creature] becomes blocked, . . .” generally triggers only once each combat for that creature, even if it’s blocked by multiple creatures. It will trigger if that creature becomes blocked by at least one creature declared as a blocker. It will also trigger if that creature becomes blocked by an effect or by a creature that’s put onto the battlefield as a blocker, but only if the attacking creature was an unblocked creature at that time. (See rule 509.1h.)