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.
I just wanted to clarify to make sure that the cards work the way I believe they do.
The crux is whether or not the entirety of the Ambush takes place during the action phase. I play Ambush on an opponent's personality using Akuma xp2.
1) Does Akuma's trait prevent him from being targeted during an Ambush?
2) Does Akuma's trait prevent him from bowing at the end of the 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.
Ambush has 2 instances of Required Targeting. "Target one of your unbowed Personalities," and "another player's target Personality."
Required Targeting must take place during Step B of playing the Action - B. Required Targeting
During the Action Phase, Akuma cannot bow or be targeted.
Since Step B happens before Ambush produces any effects (that's Step D - Action Resolves), that targeting happens during the Action Phase. You can't target Akuma during the Action phase. He can neither Ambush nor be Ambushed.
1) Does Akuma's trait prevent him from being targeted during an Ambush?
No. During the Attack Phase create by Ambush it is not considered to be the Action Phase.
During the additional phase or segment, the game is considered to be in that phase or segment, rather than in the phase or segment during which the effect occurred. For example, if a Limited action creates an attack during the Action Phase, the game is considered to be in the Attack Phase and not the Action Phase for the duration of the attack.
Of course, getting Akuma to the Ambush battle in the first place seems to be a daunting task. I suppose something like No Hiding Place could still pick him off at Home during an Ambush if you had a big enough Ranged Attack.
2) Does Akuma's trait prevent him from bowing at the end of the Ambush?
No again, for the same reason. Of course, getting Akuma to be in a battle resolution during an Ambush would be very, very difficult.
Correction to above: Ambush does not create an Attack Phase in Samurai Edition.