The close relationship between government and business in Japan makes a Tokyo location advantageous if not necessary.
Tokyo is Japan's leading industrial center, with a very high manufacturing base. This is the industrial center because it is the largest place that attracts most of the people in Japan.
Tokyo was particularly affected by an economic crash in Japan in the 1980s when the country joined as a global financial center rivaling Europe and the United States. The economic upswing led to speculation, and especially to real estate speculation. Land prices soared at the time, as did the value of the yen.
Since Tokyo is such a large city, and it attracts many people, it becomes the center of many company headquarters. The centre of tokyo also consists of Japan's government agencies, mainly because Tokyo is the political and commercial center.
Tokyo has an amazing GDP of 1.6 billion dollars, which is 600 million more than the other highest city, which is New York.