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, 9 April 2013
Goju Bunoro 4 2 HR/GC/PH - 7 0 Spider Clan • Shadowlands • Ninja • Displacer
After Bunoro enters play: Lose 2 Honor. Battle: Target a non-Unique enemy Personality: Turn all cards in his controller's provinces face-up. You may overlay a face-up Personality in one of the provinces on the target, refilling the province with the target.
Sudden Blockade 3 Open: If it is not the active player's first turn, target a province: Cards will not enter play from the province (this turn).
If a province is affected by Sudden blockade and it contains a personality. How does Bunoro interact? Is it an illegal target? if its a legal target does the overlay stop but then the person replaces the dynasty card in the province?
A player, 9 April 2013
Overlaying doesn't involve entering play. See here: For purposes of triggered effects and other things that check for the transition of entering or leaving play, rather than the state of being in or out of play:
If the overlaying card comes from an out-of-play area, such as a province, it does not enter play(even though the physical card enters play).
Sudden Blockade doesn't stop overlaying, including that from Goju Buenorro Bunoro's ability.