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, 26 January 2012
if i use the stronghold's duel, and i use yataku as the performer can i react with his reaction so long as my opponent's personality is a samurai? cause he will bow for his reaction, which means he will no longer be unbowed for the strongholds ability.
watchful eye dojo Iaijutsu Open: Even if this card is bowed, choose your performing unbowed Personality and target another players' Personality: Your performer challenges the target. He may refuse; if he did, dishonor him and gain 1 Honor. Bow the duel's loser.
kitsuki yataku Political Reaction: After an action targets a target Samurai, bow Yataku: The Samurai's controller may not choose to refuse any challenge created by the action.
Brook Cunningham (rules official), 26 January 2012
if i use the stronghold's duel, and i use yataku as the performer can i react with his reaction so long as my opponent's personality is a samurai? cause he will bow for his reaction, which means he will no longer be unbowed for the strongholds ability.
watchful eye dojo Iaijutsu Open: Even if this card is bowed, choose your performing unbowed Personality and target another players' Personality: Your performer challenges the target. He may refuse; if he did, dishonor him and gain 1 Honor. Bow the duel's loser.
kitsuki yataku Political Reaction: After an action targets a target Samurai, bow Yataku: The Samurai's controller may not choose to refuse any challenge created by the action.
In the sequence you describe, you would choose Yataku as the performer for Watchful Eye Dojo's action BEFORE you would bow him for his own action, so everything would proceed legally thus:
1. Announce the Stronghold action. 2. Choose your unbowed Yataku as its performer. 3. Choose another player's Personality as its target. 3b. If you targeted a Samurai, you can now use Yataku's Reaction, bowing him to pay its cost. 4. With the performer and target already chosen, the effects of the Stronghold's action now resolve: Yataku challenges the target, who may not refuse because of Yataku's action.