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, 27 March 2008
kanshi: Reaction: Before another player resolves a Political action: One of your target Samurai or Courtier Personalities commits seppuku in protest. The player may choose to negate his action´s effects. If he does not choose this, then after his action resolves, dishoner each Personality who performed it and he loses 5 Honor.
determination: Dark Virtue Reaction: Before you announce an action, target one of your Samurai: The action can not have its effects negated or have its targeting changed. After the action destroys any Personality, remove him from the game.
if a player choses to negate his action, is the negation negated by determination? and its useless to even play kanshi against determination?
[Mod edit: Thread title. -ZF]
Zen Faulkes (rules official), 27 March 2008
kanshi: if a player choses to negate his action, is the negation negated by determination?
Player 1 plays an action. Player 2 reacts with Kanshi. If it's player 1 using Determination on the initial action, that does not change what option he allowed to choose in response to player 2's Kanshi, due to the blind cards rule (http://rules.l5r.com/Effects#Blind_cards_rule). And Kanshi looks for the choice, not whether the effect happens.