I think there's only one... assuming it was even a game: Shenmue Gai (シェンムー 街). And it's maybe amongst the worst documented I've come across. Not "undocumented" in the sense that we didn't know it existed, but virtually all Western media called it "Shenmue City"... which from what I'm seeing, was never the game's name. Accompanying screenshots were usually from the Dreamcast (although to be fair, Dreamcast screenshots were used to illustrate what it was about when it was announced), but it's a mobile game from 2010 - it never looked like that. There's reports of it starting and ending, but nobody bothered to work out what it actually was. The service only lasted a year, and only in Japan. It was announced in conjunction with the launch of a service called "Yahoo! Mobage", which I think was/is meant to be a glorified app store that let you play mobile and PC versions of the same game, or something. Unfortunately we can't ignore this - Sega released Let's Make Baseball and Phantasy Star games for the platform, and probably loads of other things (there was a PC one fronted by Yahoo! Japan, and a mobile one fronted by DeNA - don't know the story, none of it is in English). p.s. Mobage had rivals. Someone else might need to take the lead on this - I'm still regenerating brain cells after working through the last set of Japanese mobile platforms.