Daigotsu Gahseng's text says:
Reaction: After an action's resolution ends, if you discarded a Dark Virtue card as a cost or effect of the action: Put the Dark Virtue in your hand.
Page 24 of the Celestial Edition rules book, under the When Can I Take An Action, Section F: Tidy Up, says:
Finally, if you took the action from a Strategy card in your hand, discard it.
Two questions: A) Is the discarding of the Strategy card considered a cost, or an effect of taking an action on the Strategy card? B) Can I play a Dark Virtue for an action printed on it, and then use Daigotsu Gahseng to return it to my hand after the Tidy Up step? The wording of the rulebook is somewhat ambiguous, as it seems to both permit (use of term discard) and potentially disallow this (no specification whether this is a cost, effect, or other).