Comprehensive Rules, Effects, Duration of effects: "Ongoing effects last until the end of the turn in which they occur unless otherwise indicated.
"EXCEPTION: Changes to a card’s Focus Value during a duel end after the duel ends."
until end of turn?
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.