Looking to extend your Mega Man Star Force 2
experience? You're relatively in luck! In Japan, a series of 279 Battle Cards was released in packs, and also collected into a "Perfect Guide" book. The cards, meant to fit over the DS touchscreen, feature patterns of holes that, when pressed, unlock items, characters, bosses, and other content. The book contains pictures of these cards, allowing players to see and use the patterns.
Strategy guide publisher Prima got the license for this book in North America, publishing it as the Mega Man Star Force 2 Wave Command Card Kit.
Stuff like this rarely comes out stateside, and never for $10.19 (Amazon's current price)!