When Perry returned to Japan in 1854, why did he bring more ships than he had in 1853?

In 1853, Commodore Matthew Perry arrived with a small squadron to present the U.S. demand that Japan open relations. When he returned in 1854 with a larger fleet, the additional ships demonstrated American military power and increased pressure on Japan to negotiate. The fleet was meant to persuade the Japanese government, not primarily to carry officials, train sailors, or trade goods.

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