The US has quite a presence in Japan. Over 30,000 troops. In Okinawa U.S. military installations occupy about 10% of the total land usage. Plus, the Japanese govt has to pay an annual fee as "host nation support" to the US. Looking at it from their point of view, you kind of understand why they want the troops either out totally or reduced significantly.
http://search.japantimes.co.jp/cgi-b...0100426a1.html