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, 22 August 2012
My opponent has Ryoshun's Guidance in play attacks with Hida Osote (with a follower) and another Crab personality. I defend with a personality who has Wyrmbone Katana equipped and more force than either of my opponent's personalities or the Osote follower.
I announce the action on the Wyrmbone targeting the naked Crab personality. My opponent uses Ryoshun's Guidance to redirect the Katana's action to the Osote follower.
My question is, does the Osote trait trigger in this case? Reasoning being that the Guidance's Reaction is triggered after I make my choice for the Wyrmbone's action...
Hida Osote: After Osote enters play: Discard all your other Sensei Personalities. After the first time each turn another player's action targets your Crab Clan Personality at Osote's location: The player discards a card after the action ends.
Ryoshun's Guidance: Your Personalities have +1C while they are not involved in a duel. Reaction: When another player's action would target one of your cards, discard this card: Choose another of your non-Stronghold cards at the same location. The action targets it instead, if legal.
Ben Higgins (rules official), 23 August 2012
My question is, does the Osote trait trigger in this case?
No, Osote's trait will not trigger.
You'll note the trigger of Ryoshun's Guidance, "When another player's action would target one of your cards,". The key word in this trigger is When.
According to the rules on Timing and "When" triggers: "2. Effects that alter a player’s choice, such as targeting or assignment, are written as “when (the player) would.” The timing of such a "when... would" effect occurs later than the player indicates his or her initial choice, but earlier than the point at which the targeting (or other outcome of the choice) actually happens."
As such, if your opponent would redirect the action's targeting to a non-Crab Clan Personality, you have not targeted a Crab Clan Personality, so Osote's trait cannot trigger.