It is a useful link collection. Make use of it.

yahoo!Japan http://www.yahoo.co.jp/
The reference of the map that Japan wants to go http://www.do-map.net
A Japanese postal code reference http://www.post.japanpost.jp/zipcode/@
Internet dictionary http://dictionary.goo.ne.jp/
Oota-ku homepage http://www.city.ota.tokyo.jp/