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, 5 September 2008
After October 1st, I am playing Kyuden Kyotei and have Doji Chitose at home. Personality X is at a battlefield and I control the Imperial Favor. My opponent's Personality challenges Personality X to a duel during battle. We both focus and as the focused cards are revealed, I realize that I am going to lose. I choose to increase the focus of a focused card by 1 and react with Doji Chitose to move Personality X home. Does this have any effect on the resolution of the duel?
Also, in more generic terms: at what location does a duel actually take place, and does that location have any releveance on what happens during the duel?
[Mod edit: corrected Chiotse into Chitose - LH]
A player, 5 September 2008
After October 1st, I am playing Kyuden Kyotei
The answers below are true in September too: Kyuden Kyotei's erratum changes nothing to the fact that its Reaction can be played during duels before focuses cards are revealed.
I realize that I am going to lose. I choose to increase the focus of a focused card by 1
This is quite unfortunate for your Personality X but it is too late for you to use the Reaction on your Strongold: it must be taken "before a Fate card out of play turns face-up" (emphasis mine). It implies that you don't know yet if you are going to win or lose when you take this Reaction because all focused cards are still face-down.
Does this have any effect on the resolution of the duel?
Not directly on the resolution of duel but it may matter for other effects. For example if you take this Reaction before focused cards are revealed, your Doji Chitose and Personality X are at the same location (in your home) therefore, if Personality X is about to be destroyed as a consequence of losing the duel from your opponent's action that created the duel, you may play Duty with Doji Chitose or any other honorable Samurai Personality there.
at what location does a duel actually take place, and does that location have any releveance on what happens during the duel?
Duels take place at no specific location. Usually both Personalities opposed in a duel are at the same location (e.g. a battlefield) but it does not matter. For example, an Impromptu Duel takes place while involved Personalities are in their respective controller's home, and the challenge from Fusami's Reaction is issued even if its movement effect is negated.