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.
A player, 13 February 2012
Regarding this response: http://www.alderac.com/forum/viewtopic.php?f=59&t=96100#p1271875. In particular this bolded section:
Challenges and duels are effects, but being targeted, being chosen as a performer, issuing a challenge, being challenged or entering a duel does not change in itself the state, stats, keywords, traits or any other aspect of any Personality, so they are not effects "on" any Personality. Thus, these effects are not delayed by Halls of the Forgotten, nor negated by Goju Yurishi's Reaction.
All of the EE battle duels require targeting an enemy personality. If Yurishi was at a different battle than the current one he would not be a legal target for these duels. Therefore doesn't his own wording negate the effect of the duel?
Reaction: After another player's Battle action targets Yurishi: He disappears into the shadows. Move him home. If he is no longer a legal target for the action, negate its effects on him.
Cheers UK Ronin
Alex Jones (rules official), 13 February 2012
Therefore doesn't his own wording negate the effect of the duel?
No, because becoming an illegal target of an action after being legally chosen as a target does not of itself have any consequences, which is why Yurishi's Reaction has to explicitly state that it negates effects.
A player, 13 February 2012
based on this answer I am very confused: http://www.alderac.com/forum/viewtopic.php?f=59&t=96214#p1271897
UK Ronin wrote: Therefore doesn't his own wording negate the effect of the duel?
No, because becoming an illegal target of an action after being legally chosen as a target does not of itself have any consequences, which is why Yurishi's Reaction has to explicitly state that it negates effects.
Alex
So you are saying that because he was a legal target when chosen, even if he uses the Reaction to move home, becoming a now illegal target and hence triggering the last portion of his Reaction's effect. The duel still occurs? Despite his Reaction quite clearly saying the effect is negated?
Reaction: After another player's Battle action targets Yurishi: He disappears into the shadows. Move him home. If he is no longer a legal target for the action, negate its effects on him.
So what actions can he negate with his reaction?
Cheers UK Ronin
Alex Jones (rules official), 14 February 2012
based on this answer I am very confused: http://www.alderac.com/forum/viewtopic.php?f=59&t=96214#p1271897
So you are saying that because he was a legal target when chosen, even if he uses the Reaction to move home, becoming a now illegal target and hence triggering the last portion of his Reaction's effect. The duel still occurs? Despite his Reaction quite clearly saying the effect is negated?
Reaction: After another player's Battle action targets Yurishi: He disappears into the shadows. Move him home. If he is no longer a legal target for the action, negate its effects on him.
So what actions can he negate with his reaction?
Cheers UK Ronin
For starters it's important to realise that Yurishi's Reaction isn't a blanket "negate the action" - he negates an action's effects on him.
A duel is an effect (usually of an action), but it's not an effect on either Personality, so Yurishi's Reaction doesn't negate it. However, he will negate any effects of the duel on him, such as destroying, moving or bowing the loser.