Why did Japan open its ports to U. S. trade?

From what I remember,  according to the terms of the treaty, Japan would protect stranded seamen and open two ports for refueling and provisioning American ships: (Shimoda and Hakodate).  As a result, Perry's treaty provided an opening that would allow future American contact and trade with Japan.

well, there are a lot of places we get information about earth from. like science classes, websites, books, newspapers, etc.