The Treaty of Kanagawa, signed in 1854 between the United States and Japan, ended Japan's policy of isolation from the rest of the world, opening up trade and diplomatic relations between the two countries. This treaty marked the beginning of Japan's modernization and transformation into a major world power in the following decades.
Answer in one sentence
The Treaty of Kanagawa marked the end of Japan's isolation and the beginning of its modernization and emergence as a world power.
