I already know that multiple instances of flanking stack, and each are triggered separately. But I’m a little bit rusted (haven’t seriously played in about a year), and I just can’t recall if there’s a step in which I can do something at instant speed (say, put a Sidewinder Sliver in play with Aether Vial or Colledcted Company) after opponent has declared blockers but before said blockers actually become blocking creatures (the state that will effectively trigger flanking).
Basically, can I ambush a blocker this way, or is it too late already by the time I get priority to do so, because the moment flanking would have triggered is already past?
Declaring blockers is the first thing that happens during the declare blockers step (C.R. 509.1). In general, afterAfter blockers are declared, the appropriate abilities (such as flanking), if any, trigger and go on the stack, and only after those abilities, if any, go on the stack do players get priority to cast instant spells (such as Collected Company) or activate abilities (such as Aether Vial's activated ability) (C.R. 509.1i, 509.3, 117.5, 117.1a-b, 702.24).
EDIT: Edited after comment 4 was posted.
EDIT (Sep. 24): Some rules were renumbered in the meantime.
In the specific case I mentioned in my post, if I understand correctly, it is already too late to add flanking creatures to the battlefield, right? The last moment in which I can do so and make sure flanking will trigger is before blockers are declared, right?
In the specific case I mentioned in my post, if I understand correctly, it is already too late to add flanking creatures to the battlefield, right? The last moment in which I can do so and make sure flanking will trigger is before blockers are declared, right?
You can cast Collected Company or activate Aether Vial's last ability after attackers are declared and before blockers are declared (C.R. 508.2, 117.3d, 117.1a-b), but you have to do so without knowing whether your opponent will then block with any creatures (including whether any of those creatures will block a creature you bring to the battlefield due to that spell or that ability). Also, in certain rare cases, a creature can be made to block after blockers are declared (e.g., by Balduvian Warlord's ability). But no player has priority to cast spells or activate abilities while blockers are declared (C.R. 703.3, 509.1).
EDIT (Sep. 24): Some rules were renumbered in the meantime.
if there’s a step in which I can do something at instant speed (...) after opponent has declared blockers but before said blockers actually become blocking creatures (the state that will effectively trigger flanking).
Basically, can I ambush a blocker this way, or is it too late already by the time I get priority to do so, because the moment flanking would have triggered is already past?
No, there is no such step. You can't ambush an opponent this way.
The declaration of blockers is covered by rule 509, which is divided into quite a few steps:
-defending player announces blocking creatures according to rule 509.1
-those creatures officially become blocking creatures when rule 509.1g is reached
-triggers (such as Flanking) happen next, as per rule 509.1i
Only when the game reaches rule 509.4 are players allowed to 'do stuff'.
(some weird corner cases shenanigans are made possible by rule 509.1e, but I don't think those could apply here)
Basically, can I ambush a blocker this way, or is it too late already by the time I get priority to do so, because the moment flanking would have triggered is already past?
1st, GP Toronto Sunday Super Series 2016 : Ally Company RWBG
Top 8, PPTQ Shadows over Innistrad : Boros Humans WR.
Use a hypergeometric calculator for your deckbuilding maths,
and use TopDecked to manage your decks and collection on your Apple or Android device.
In general, afterAfter blockers are declared, the appropriate abilities (such as flanking), if any, triggerand go on the stack, and only after those abilities, if any, go on the stack do players get priority to cast instant spells (such as Collected Company) or activate abilities (such as Aether Vial's activated ability) (C.R. 509.1i, 509.3, 117.5, 117.1a-b, 702.24).EDIT: Edited after comment 4 was posted.
EDIT (Sep. 24): Some rules were renumbered in the meantime.
In the specific case I mentioned in my post, if I understand correctly, it is already too late to add flanking creatures to the battlefield, right? The last moment in which I can do so and make sure flanking will trigger is before blockers are declared, right?
1st, GP Toronto Sunday Super Series 2016 : Ally Company RWBG
Top 8, PPTQ Shadows over Innistrad : Boros Humans WR.
Use a hypergeometric calculator for your deckbuilding maths,
and use TopDecked to manage your decks and collection on your Apple or Android device.
EDIT (Sep. 24): Some rules were renumbered in the meantime.
The declaration of blockers is covered by rule 509, which is divided into quite a few steps:
-defending player announces blocking creatures according to rule 509.1
-those creatures officially become blocking creatures when rule 509.1g is reached
-triggers (such as Flanking) happen next, as per rule 509.1i
Only when the game reaches rule 509.4 are players allowed to 'do stuff'.
(some weird corner cases shenanigans are made possible by rule 509.1e, but I don't think those could apply here)
RULES OF MAGIC :
http://magic.wizards.com/en/game-info/gameplay/rules-and-formats/rules