Inujima
 The Seto Inland Sea (瀬戸内海), surrounded by Honshu, Shikoku and Kyushu, is a veritable treasure trove of adventure. You can take the longest suspension bridge in the world, Akashi-KaikyÅ, to Awaji Island to feast on onions. From Awaji, or Shikoku’s Tokushima prefecture, there are the turbulent Naruto whirlpools where Japan’s fastest currents make one…