Thanks to an update post from GungHo's Puzzle & Dragons website, we already know that 2014 for Taiko games will start with another returning collaboration!
Like for the last time, the Taiko no Tatsujin dungeon (for P&D) and Walking Through The Towers as a free playable song (for Taiko +) will be available for everyone to play from January 6th to 12th. We don't know yet if the Taiko side of the collaboration will involve additional content for Taiko iOs players, but rest assured that will be probably explained by the Taiko Team itself in one of the first 2014 blog entries.
