Many of the large ships of war destined to visit Japan have not yet arrived in these seas . . . And [I], as evidence of friendly intentions, have brought but four of the smaller ones, designing, should it become necessary, to return to Edo [next] spring with a much larger force. But it is expected that your imperial majesty will render such return unnecessary, by acceding at once to the very reasonable overtures contained in [President Fillmore's] letter. –US Navy Commodore Matthew C. Perry, 1853 What implicit threat is contained in Commodore Perry's letter? He could bring an army to Japan. He could tell the president that Japan was not cooperative. He could return with a larger force and attack Japan. He could attack Japan with his four ships.