So a province with the Plains holds two Dynasty cards, and Susaiken says "Once per turn, you may refill one of your provinces face-up." Does this allow you to flip both cards in the Plains province face-up as they are both part of one province? The way it's worded, you should be able to refill both face-up, but it's always good to check.
Plains of Otosan + Daigotsu Susaiken
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.
So a province with the Plains holds two Dynasty cards, and Susaiken says "Once per turn, you may refill one of your provinces face-up." Does this allow you to flip both cards in the Plains province face-up as they are both part of one province? The way it's worded, you should be able to refill both face-up, but it's always good to check.
This would only be possible if you were refilling both slots of the Province simultaneously. Since provinces refill automatically when they're empty (see CR on Provinces), generally the instant you buy something, it refills and you can trigger Susaiken then.
If both cards in the Province were refilling simultaneously (for instance, via an effect that said to discard all cards in the province), then Susaiken could refill both face up.