Answer:
There were several reasons why the United States became interested in revitalizing contact between Japan and the West in the mid-19th century. First, the combination of the opening of Chinese ports to regular trade and the annexation of California, creating an American port on the Pacific, ensured that there would be a steady stream of maritime traffic between North America and Asia. Then, as American traders in the Pacific replaced sailing ships with steam ships, they needed to secure coaling stations, where they could stop to take on provisions and fuel while making the long trip from the United States to China. The combination of its advantageous geographic position and rumors that Japan held vast deposits of coal increased the appeal of establishing commercial and diplomatic contacts with the Japanese. Additionally, the American whaling industry had pushed into the North Pacific by the mid-18th century, and sought safe harbors, assistance in case of shipwrecks, and reliable supply stations. In the years leading up to the Perry mission, a number of American sailors found themselves shipwrecked and stranded on Japanese shores, and tales of their mistreatment at the hands of the unwelcoming Japanese spread through the merchant community and across the United States.
The Perry Expedition led directly to the establishment of diplomatic relations between Japan and the western Great Powers, and eventually to the collapse of the ruling Tokugawa shogunate and the restoration of the Emperor
