This game was supposedly confirmed, then it was in uncertain status, now it is back on track. It was just a little over a month ago that Yu Suzuki himself spoke of his uncertainty as to whether or not a third Shenmue game would be produced. The series' creator said that the story was mostly finished, but no official plans existed to make the game. More recently, news confirming the game's impending production has come forward.
Developer Sega-AM2 has announced that it will be the company responsible for the development of Shenmue III, and also noted that the planning process is not quite 100% complete. Details regarding a targeted release date and the console on which the game will appear were not discussed.
Sega-AM2 did not specify how much or how little the decision was assisted by the number of letters the company received on the matter. More details are said to be coming in September.