Unfortunately, the greatest train line in Japan (in my humble opinion) is the Tokyu Toyoko/Minato Mirai line. That thing is great. Straight shot from Shibuya to Motomachi. It hits Jiyugaoka, Yokohama, Hiyoshi, Queen's Square, Yamashita Park and Chinatown. Motomachi, Minatomirai, and Chukagai are all MUST SEE places in Yokohama. I mean before Sept. 11th, who would go to NYC without seeing the World Trade Center? That's like going to Yokohama and not seeing the tallest building in Japan. Many of the trains were new last year and really clean. Unfortunately, it's a separate company from JR so any JR pass won't help. Sorry, I used to live in Yokohama, so I'm a little biased.