A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
Single Combat: "Reaction: Immediately before allies are invited to join an attack or defense of a province, prevent units of players other than the Attacker or Defender from being committed or moving into battles this turn."
Can I wait for allies to be invited before I play this reaction, or must I play it before allies are invited?
Single Combat: "Reaction: Immediately before allies are invited to join an attack or defense of a province, prevent units of players other than the Attacker or Defender from being committed or moving into battles this turn."
Can I wait for allies to be invited before I play this reaction, or must I play it before allies are invited?
See Attack Phase: Declaration Segment.
"Invite Allies" (aka "Call for Allies") is a defined step in the Declaration Segment of an Attack Phase. Single Combat triggers before this timing point, rather than before an invite is actually made.