If you're ever in Tokyo and feel like a taste of Okinawa without actually leaving Tokyo, then Okinawa Town is the place to go. And Syuri Seimen is the place to try Okinawa Suba (or Soba). It's not actually ramen, but it's pretty darn close. With homemade noodles, two types of soup, and even a lucky lion statue that promises a lifetime of happiness, Syuri Seimen is a great place to enjoy the fresh Okinawan ingredients while getting hammered off some Okinawan Sake.
Take the Keio Line to Daitabashi Station. Walk North to the main street and you should be able to see the Okinawa Town entrance on the other side. Cross over using the pedestrian bridge and head down the Okinawa Town street. It'll be on your left. They open from 11:30am to 3pm at lunch and 5pm to 11pm for dinner. Closed on Wednesdays.
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