Japan is launching a new high-speed bullet train, or shinkansen, extension on Saturday that will make an under-the-radar prefecture far more accessible to travelers. The coastal Fukui Prefecture is some 185 miles west of Tokyo. The new train will pass through the city of Fukui, the town of Awara and other places guidebooks rarely mention, before reaching the port town of Tsuruga, adding some 78 miles to the Hokuriku Shinkansen's existing Tokyo-to-Kanazawa service. Once it begins on March 16, the route will open a door to a part of Japan — known for dinosaurs, Zen meditation and soothing hot-spring baths...