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, 16 June 2010
I think Brook mentioned in an unofficial capacity that the additional card brought into the focus pool from Shadow's Talon doesn't give Kado a +1/+1 bonus, because it was put directly into the focus pool, and not directly focused.
However the rules wording for Focus: http://rules.l5r.com/CE_Glossary_F#Focus
Focus
To put a card into one’s focusing area during a duel.
So if I focused 2 cards with Kado in a duel, and one of them was a Shadow's Talon, which put a third card in my focus pool, would Kado then gain an additional +1F/+1C?
Zen Faulkes (rules official), 16 June 2010
(I)f I focused 2 cards with Kado in a duel, and one of them was a Shadow's Talon, which put a third card in my focus pool, would Kado then gain an additional +1F/+1C?
No.
The glossary definition is correct, but the glossary definition shouldn't be read in isolation from the rest of the rules, namely the rules for challenges and duels, which spell out in considerably more detail what focusing means. Focusing is a process allowed by the rulebook, not anything that accomplishes some end result.
Will try to clarify the glossary entry Real Soon Now(TM).