Ring of Earth stops movement from a Battle action. Golden Plains' ability is a Battle/Engage. If GPotU is used as an Engage, can I use RoA to stop the movement?
Ring of Earth vs. Golden Plains of the Unicorn
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.
Ring of Earth stops movement from a Battle action. Golden Plains' ability is a Battle/Engage. If GPotU is used as an Engage, can I use RoA to stop the movement?
No - there's ample precedent on this, if an action has two possible types, when the action is being taken it only counts as the type it's being used at at that time.
So if The Golden Plains of the Unicorn's ability is used as an Engage, you cannot stop it via Ring of Earth.
On: Ring of Earth