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, 31 January 2011
DO reactions, such as Strength of Bamboo cause me to target my personality with a -3 force penalty if Temporizing Ground is in play? Thanks,
Temporizing Ground: Terrain Battle: After the resolution of each action, except this one, the player who took the action targets one of his unbowed Personalities or Followers with a Force of 1 or greater at the current battlefield and gives that card -3F.
Strength of Bamboo: Heroic Reaction: After an action targets your Hero Perosnality: Negate his destruction from the action's effects. Give him +1F
Brook Cunningham (rules official), 31 January 2011
DO reactions, such as Strength of Bamboo cause me to target my personality with a -3 force penalty if Temporizing Ground is in play? Thanks.
Yes. Reactions are "actions".
Anything preceded by the boldface words "Battle", "Open", "Limited", and/or "Reaction" is an action, and counts for effects that look for "actions" being taken, resolving, etc.