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, 19 December 2014
Can you take the Dynasty Legacy action even if you have no Legacy Cards remaining in your deck or provinces?
Example Situation:
I am playing Shika Sensei and have a Rich Vein and a scout face up in my provinces. I recruit the Rich Vein and interrupt to find the next 3 cards are holdings. Can i announce the Dynasty Legacy Action, removing a card from my hand, search and fail to find a Legacy card, then shuffle my Dynasty deck?
Alex Jones (rules official), 26 December 2014
Can you take the Dynasty Legacy action even if you have no Legacy Cards remaining in your deck or provinces?
Example Situation:
I am playing Shika Sensei and have a Rich Vein and a scout face up in my provinces. I recruit the Rich Vein and interrupt to find the next 3 cards are holdings. Can i announce the Dynasty Legacy Action, removing a card from my hand, search and fail to find a Legacy card, then shuffle my Dynasty deck?
Yes.
You are not required to know the contents of your decks.
Alex Jones (rules official), 2 April 2015
Note that if you do this, you will lose the game: Dynasty, (*): Remove a card in your hand from the game to search your deck and Provinces for a Legacy Holding and Recruit it. If you fail to find one, you lose the game.
Alex