If you haven't been to Yokohama, Japan, maybe the following information will be helpful.
Pacifico Yokohama, the Nippon2007 venue, is at Minato-Mirai area.
http://en.wikipedia.org/wiki/Minato_Mirai_21
For shopping, Landmark Tower and buildings around the tower is modern area.
http://www.yokohama-landmark.jp/english/index.html?pagechange=91
you can also walk to Isezaki-mall from Minato-mirai. You can also get there by train. The nearest station is JR Kannai. But I think it is relevant time for walk :-)
http://en.wikipedia.org/wiki/Isezakicho
http://en.wikipedia.org/wiki/Kannai_Station
Isezaki-mall is not so big as Yokohama station area but I think it is good for those who don't wanna go so far.
You can walk to Yokohama Museum of Art if you like art. some Japanese art are at permanent exhibits rooms.
http://www.yaf.or.jp/yma/en/
Yokohama is famous for beautiful night view. You can find many beautiful sight especially at high-rise building. I also like the Ferris wheel of Yokohama cosmo world in night.
Link(s):
https://www.welcome.city.yokohama.jp/convention/eng/delegates/guide_kids.html
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If you like old temples, I recommend Kamakura area, 30-40 mins from Minato Mirai.
To get to Kamakura from Minato-Mirai, go to JR Sakuragicho station, and get Yokohama station then change trains to JR Yokosuka-Sobu line.
http://en.wikipedia.org/wiki/Kamakura%2C_Kanagawa
The second largest Buddha statue in Japan is in Kamakura area. The nearest station for the Buddha is Hase. From Kamakura station, get Enoshima-Dentetsu line.
http://en.wikipedia.org/wiki/K%C5%8Dtoku-in
I like areas around Kamakura station and Kita-Kamakura station. I also like to walk from Kamakura-station to Kita-Kamakura station but it takes time.
- Susumu Miyama, Shigetaka Kaneko
- Kamakura: Its History, Sights and Landmarks (Paperback)