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, 29 June 2011
Relevant card text:
Whispers of the Dying Sun Choose a (non-Stronghold) card in play. Each of its base abilities may be used one additional time this turn.
Border Keep Unique Bow this card: Produce 2 Gold. Limited: If it is your first turn: Put one or more cards in your provinces at the bottom of your deck, refilling the provinces face-up. Limited: Once per game: Put one or more cards in your provinces at the bottom of your deck, refilling the provinces face-up.
If a player resolves Whispers of the Dying Sun in his 2nd turn, choosing Border Keep, he gets another use of each of its ability, but since it is no longer his first turn, he cannot use the first, correct? He can use the second one because granting an additional use of an ability for a period of time (here, this turn) also grants an additional use for any larger period of time containing the first (here, the game), regardless of whether he used it in his first turn, correct?
Zen Faulkes (rules official), 29 June 2011
If a player resolves Whispers of the Dying Sun in his 2nd turn, choosing Border Keep, he gets another use of each of its ability, but since it is no longer his first turn, he cannot use the first, correct?
This is the current ruling: viewtopic.php?f=59&t=79042:
"REVERSAL [March 17th 2010]: due to the text "this turn" on Whispers of the Dying Sun, both the initial use and the additional use MUST occur in the SAME TURN. Thus, if the "once per game" ability on Border Keep has been used in a previous turn, you CANNOT use Whispers of the Dying Sun to get an "additional" use out of it on a later turn."