the following year, perry returned with seven ships and forced the "shōgun" to sign the "treaty of peace and amity", establishing formal diplomatic relations between japan and the united states, known as the convention of kanagawa (march 31, 1854). within five years japan had signed similar treaties with other western countries. the harris treaty was signed with the united states on july 29, 1858. these treaties were widely regarded by japanese intellectuals as unequal, having been forced on japan through gunboat diplomacy, and as a sign of the west's desire to incorporate japan into the imperialism that had been taking hold of the continent. among other measures, they gave the western nations unequivocal control of tariffs on imports and the right of extraterritoriality to all their visiting nationals. they would remain a sticking point in japan's relations with the west up to the start of the 20th century.