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.
Bayushi Hisato, Mountain's Shadow Dojo, and UtakuTayoi all refer to moving a personality to "another battlefield." Does another battlefield refer to: 1) A battlefield the unit in question is not currently at 2) A battlefield other than the current one
More specifically, could Mountain's Shadow Dojo be used to move a Crane clan samurai from a different battlefield to the current one and shoot someone at the current battlefield?
The Rule of Location: If a Battle action is on a card in a unit (a Personality or attachment in play), the unit must be at the current battlefield; and any cards in units must be at the current battlefield to be legally targeted by a Battle action.
EXCEPTION: A Battle Action can target or be taken by a card in a unit at another location if its costs or effects say they can move the unit to the current battlefield. Choices within the action must then be taken, if possible, such that they do move the unit there.
This was taken from the Comprehensive Rules on Battle.
The Rule of Location keeps people from taking Actions during the Current Battle that actually play out exclusively at other Battlefields or Homes. If you are in the Combat Segment for Battlefield A you shouldn't be starting duels between two Personalities at Battlefield B! They have to wait their turn.