Is it legal to move Bayushi Chikayo to the current battlefield if there is no enemy unit there and move home an opposed courtier from another battlefield?
[Mod edit - Corrected syntax - LH]
Bayushi Chikayo
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.
Battle: Move your target opposed Courtier home. Move Chiyako to the current battlefield. If the Courtier moved, the enemy leader loses 2 Honor.
No, it is not legal to use Bayushi Chikayo's ability if there is no enemy unit at the current battlefield and that action can not target your opposed Courtier at another battlefield, per the first part of the Rule of Location: "Any cards in units must be at the current battlefield to be legally targeted by a Battle action."
Bayushi Chikayo's Battle action's target is an opposed Courtier you control, who is a card in a unit, therefore he must be at the current battlefield and be opposed there.