Keiji Inafune, best known for Dead Rising and Mega Man, is hard at work on a new game. This is unconfirmed, but according to the upcoming issue of Famitsu, the game is called Yaiba. All that's currently known is that the game is a zombie title. More details, including platforms, are forthcoming. Sit tight.
Update: According to the Famitsu article, the concept behind the game is "zombie", "action", "ninja", and "mecha". The game is supposed to be a "new type of Inafune zombie game."
More details should become available when the game's official site launches tomorrow. There's talk online in Japan that this game could be a Wii U title. Have a blurry look at the game's first concept art and its logo.