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, 6 June 2013
If I have Apprentice Shinobi attached to a personality that then gets destroyed and put under The Tachikaze will it continue to gain force bonuses for any ninja actions I take that turn?
Apprentice Shinobi: Keywords Ninja Text After the resolution of a Ninja action: Give this card +1F.
The Tachikaze eywords
Boat • Retainer Text After an action resolves whose effects destroyed your Follower with a Gold Cost of 1 or more: You may put it face-up under this card. Battle/Limited: Any number of times per turn, target your Personality: Attach a Follower from under this card to him, paying all costs.
Thank you,
A player, 6 June 2013
"Under The Tachikaze" is an out-of-play area, which means your Apprentice Shinobi is out of play, and in that game state "triggered traits do not trigger" (second bullet). So, Ninja actions you play while Apprentice Shinobi is under The Tachikaze won't give it the Force bonuses. (However, it'll still retain until the turn ends any ongoing Force bonuses it had received from its trait before it left play)