What incident forced Japan to acknowledge the interests out of outside nations?

In 1853, the United States sent four naval vessels under the command of Commodore Matthew Perry to 'encourage' the Japanese Shogun to sign a trade treaty with America. Japan had no navy, so when Perry's ships (including two steamers) sailed into Tokyo Bay, the Japanese signed a treaty allowing American traders to sell goods into Japan and buy raw materials and other items for sale into the United States and other markets.