From DominionStrategy Wiki
You may trash a card from your hand.
+1 Card per card the player to your right trashed on their last turn.
 Official FAQ
- You draw cards even if you did not trash a card.
- One way to keep count of the number of cards trashed is to put them on the trash sideways.
 Other Rules clarifications
- You get +1 Card for every time the player to your right trashed a card during their last turn, even when they trash a card they already trashed that turn. For example, if they trashed the same Fortress twice, your Goatherds will give you +2 Cards. 
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