This treaty was forced on Japan by the gunboat diplomacy of Britain and the United States who argued that Japan had a moral duty to adopt a policy of Free Trade. It ended the policy of isolation which had been maintained since 1635. The treaty allowed US to trade via the ports Shimoda and Hakodate and paved the way for the Harris Treaty of 1858 which would considerably extend Japanese compliance with Western demands. See the “Opening of Japan” for more information.
Editors. "Treaty of Kanagawa". The Literary Encyclopedia. First published 12 December 2007
[http://www.litencyc.com/php/stopics.php?rec=true&UID=4957, accessed 20 June 2013.]