One of the most popular games in Japanese arcades is not Street Fighter IV or Tekken. It’s actually a mahjong game. You often see more cabinets for MJ4, than other arcade games, out numbering them by two to one usually.
People can buy a card to save their info on, and then play against other opponents all over Japan via the internet. It also has a touch screen to make it really easy for anyone to play.
The machines are usually busy everytime I see them. I haven’t played it myself due to it’s high usage of the Japanese language. Looks fun though. I’m sure this is Sega’s real bread winner.