A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from the Wayback Machine (its copy), so posts 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, 21 April 2005
Simply stated,
I declare a naval invasion.
I perform a ranged attack for my first naval action and use Tsuruchi Technique's reaction to increase that RA.
Can my opponent then play "Fall on your Knees" to cancel that reaction, or do the Naval rules ("No player may take actions (including Reactions) or bring cards into play between the start of the Battle Actions Segment and the first Battle or Open Action opportunity except for Reactions to that Action) prevent my opponent from playing "Fall...?"
Zen Faulkes (rules official), 22 April 2005
I declare a naval invasion. I perform a ranged attack for my first naval action and use Tsuruchi Technique's reaction to increase that RA. Can my opponent then play "Fall on your Knees" to cancel that reaction?
Yes. You have taken your opportunity for a Battle or Open action.