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 April 2012
Can the extra ranged attacks from Koshin Keep target through followers if the first shot is by Toritaka's ability?
The scenario:
1. Koshin Keep Recon Reaction. 2. Toritaka uses her ability and a ranged attack is made against a personality with attached followers, but does not kill him.
Can the "and you may take an additional Ranged Attack Battle action that may only target the same card" allow other ranged attacks in her army to attack the personality, or is she SOL because other ranged attacks would need to target the followers?
Koshin Keep Recon Reaction: After engaging: You have Reconnaissance at the current battlefield. Until this battle ends, your Ranged Attacks that do not destroy their target have the additional effects, "reduce the target's Force by the Ranged Attack's strength and you may take an additional Ranged Attack Battle action that may only target the same card".
Toritaka Chokichi Battle: Bow your performing Follower: Ranged 4 Attack which may target a Personality with attached Followers if you have Reconnaissance.
Ben Higgins (rules official), 26 April 2012
Can the extra ranged attacks from Koshin Keep target through followers if the first shot is by Toritaka's ability?
The scenario:
1. Koshin Keep Recon Reaction. 2. Toritaka uses her ability and a ranged attack is made against a personality with attached followers, but does not kill him.
Can the "and you may take an additional Ranged Attack Battle action that may only target the same card" allow other ranged attacks in her army to attack the personality, or is she SOL because other ranged attacks would need to target the followers?
As was ruled here with Strategic Strike, the follow-up Ranged Attacks from Koshin Keep do not inherit an special targeting allowances from the initial Ranged Attack.
In your example, you would need to follow up with another Ranged Attack that could target the Personality past their Follower, either with another copy of Chokichi or a Strategic Strike.