Ambush and Weigh the Cost (L5R rules board)

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, 3 March 2009

Can I play Weigh the Cost in a battle caused by Ambush, or does the lack of a Province prevent me from doing so?

Card text:

Ambush Limited: Target one of your unbowed Personalities: Create a battlefield (not at any province). Assign your Personality to attack there. Assign another player’s target Personality to defend there, even if bowed. No other units may move there. Fight a battle there. After it ends, lose 5 Honor. Gold 0

Weigh the Cost Battle: Move one of your target Samurai Personalities home: Bow him. Raise or lower the current battlefield’s province’s strength by 2. You may target a Personality in the current enemy army and give him -3F.

Thanks, Mark

A player, 3 March 2009

Can I play Weigh the Cost in a battle caused by Ambush(?)

Yes.

This is a variation of "Is an action legal if an effect can't happen?" as explained in the FAQ.