Commercial expansion in Asia involved diplomatic entreaties with two important nations, China and Japan. The "China Market" was always a significant lure for American merchants who had engaged in trade with the declining empire since the 18th century. Following the conclusion of the First Opium War in 1842, Britain forced China to grant it special privileges, including exclusive British use of coastal ports. Not wanting to miss out on similar opportunities, President John Tyler asked Caleb Cushing of Massachusetts to undertake a mission to open Chinese ports also to American trade. In 1844, Cushing negotiated the Treaty of Wangxia. This agreement granted to American merchants the same rights as Britain based upon the "most-favored-nation" principle. Access to Japan, a nation mired in two centuries of seclusion, proved more difficult for the United States. Determined not to be rebuffed as past missions had been, Commodore Matthew C. Perry decided on a show of force. On July 14, 1853, Perry and his flotilla of what the Japanese termed "black ships" arrived off of Edo. Perry presented to representatives of the Japanese shogunate a letter from President Millard Filmore requesting the establishment of commercial relations. Masking an implied military threat, Perry announced that he would depart but come back the next year to receive a reply from the shogunate. Returning to Edo Bay the following February, Perry waited two weeks before disembarking his ship to a gracious reception by the Japanese. On March 31, the Commodore and his Japanese counterparts concluded the Treaty of Kanagawa, which guaranteed protection for shipwrecked sailors and opened two remote ports for trade and as sources of coal for American vessels.