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, 11 July 2010
Shinjo Naota reads:
Unicorn Clan • Samurai • Cavalry • Scout • Wanderer Naota has +2F while a Terrain is in play at his battlefield. Naota has +2F while any Regions are attached to his battlefield's province.
Unfamiliar Ground reads:
Terrain Battle: Bow each card with 5 or higher Force now at this battlefield. If a card's effect destroys this Terrain iduring this battle, straighten all cards it bowed.
When does Naota get the force bonus? Is it as a the terrain is played or after it resolves? Basically, if I play Unfamiliar Ground at a battlefield where Naota is present will he bow?
Zen Faulkes (rules official), 11 July 2010
(I) I play Unfamiliar Ground at a battlefield where Naota is present will he bow?
Yes.
http://rules.l5r.com/CE_Glossary_T#Terrain: "If requirements, costs and any required targeting of a Terrain action have been met, the Strategy card enters play at the current battlefield as a rulebook effect, before the Terrain action resolves."
Terrain enters play, force bonus gained, Terrain's effects start to happen, and you can bow that Unicorn, thankyouverymuch.