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, 30 August 2010
Hi
Can i play Choose Your Fight even if there are no other terrains in play at the current battlefield to play it and draw a card? So that i dont destroy all other terrains in play.
Choose Your Fight
May be played even if there is already a Terrain at the current Battlefield. Battle: Choose your performing Tactician: Destroy all other Terrains in play. Draw a card.
Thx in advance
Zen Faulkes (rules official), 30 August 2010
Can i play Choose Your Fight even if there are no other terrains in play at the current battlefiel to play it and draw a card?
Note that the card says, "May be played even if there is already a Terrain at the current Battlefield." Not, Can only be played" or something similar. It's an option to override a rule.
As for whether one effect occurs if another can't:
http://rules.l5r.com/CE_FAQ#Is_an_actio ... _happen.3F http://rules.l5r.com/CE_FAQ#If_one_effe ... _happen.3F