If I bow he personality performing the ambush before he assigns, would he be able to assign to the battlefield or would that part of the action be illegal?
Ambush and Michio exp
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.
Battles created by a card effect that does not create an Attack Phase are treated as normal battles, except:
* Such battles are (slightly) delayed effects that begin once the action or trait that created them has resolved, and the opportunity to play Reactions to the end of the action or trait has passed, in a manner similar to additional phases and actions. [CHANGED June 3 2008]
* Such battles have no Declaration or Maneuvers segments. Assignment and battlefield creation prior to such battles happen through card effects, and there is no opportunity to invite allies.
Ambush: Limited: Target one of your unbowed Personalities: Create a battlefield (not at any province). Assign your Personality to attack there. Assign another player’s target Personality to defend there, even if bowed. No other units may move there. Fight a battle there. After it ends, lose 5 Honor.
Michio exp: Reaction: After an action resolves: Bow or straighten a target Personality who performed it.
Thus:
1. Your opponent announces Ambush. 2. He declares the required targets: his performing Personality and your Personality. 3. He pays costs: none. 4. He resolves Ambush's effects: He creates a battlefield; he assigns his Personality to attack. He assigns your Personality to defend. He creates the delayed effects of "Fight a battle there" and "After [the battle] ends, lose 5 Honour." 5. Ambush has now resolved; you may take Reactions, including using Michio exp's ability. You bow his attacking Personality. 6. After all players have passed their opportunity to play Reactions to Ambush having resolved, the battle is fought. 7. After the battle ends, he loses 5 Honour.
On: Michio