Template:Infobox Item Happy pieces are items used for unlocking happy card side stories. To unlock the first side story of a 2☆ card, 200 happy pieces are needed. To unlock the second side story of a 2☆ card, 1000 happy pieces are needed. To unlock the second side story of a 3☆ card, 2000 happy pieces are needed. To unlock the second side story of a 4☆ card, 4000 happy pieces are needed.