A fan found an advertisement for an odd cross-promotion going on between the forces behind Hatsune Miku, the Vita game, Samurai & Dragons, and Famitsu magazine. In it, you will get a free Hatsune Miku majuu (magical monster) card from the Samurai & Dragons game when you pick up the upcoming issue of Famitsu. (On sale on August 30th)
It does not seem to be a real cardboard card, but rather it will include some way (probably a code or serial number) that will allow you to obtain the Hatsune Miku "Singing Princess" card within the game. Here is what a more standard majuu card looks like.
Could Miku get you to join up in the Samurai & Dragons game?