John Kendrick is the first American known to have visited Japan, commanding two exploration ships in 1791. Various American explorers and trading vessels visited Japan in the next 50 years, until the United States and Japan established formal relations in 1854, when Commodore Matthew Perry of the U.S. Navy persuaded Japan to open to international trade, with the Convention of Kanagawa. Perry's mission was explicitly to establish a trade treaty for the U.S., and using the threat of a bombardment from his steam-powered "Black Ships," against the almost medieval Japanese military, Perry insisted on presenting a letter of terms from President Millard Fillmore.
In 1860, using Japan's first propellor-driven steam ship, a delegation traveled, via San Francisco and Panama, to Washington D.C., to establish a Japanese embassy in the U.S. for the first time. Attempts to alter the terms of the Perry treaties were rejected, but Japan did receive help from the U.S. to modernize its economy, armed forces and constitution. Trade and diplomatic relations between the two rapidly modernizing nations were strong, with American and Japanese military serving together during the Boxer Rebellion against foreign traders in China (1898-1901), and among the allies in World War I after the U.S. entered the war in 1917.
During the inter-war period, however, relations deteriorated as Japan's imperial ambitions grew, beginning with the Manchurian Incident in 1931, which was used as a pretext for the invasion of mainland China. In 1934, Japan broke the terms of an international naval treaty, as it built up its forces. The United States had its own interests in the Pacific, including the Philippines, which allowed it to control oil supplies to Japan, which imported 90 percent of all its oil, 80 percent of which came from the U.S. Japan's signing of the Anti-Comintern Pact with Nazi Germany in 1936, the Nanking Massacre of 1937 and a full-scale Sino-Japanese war, did nothing to placate the concerns of America.
It was not until August 1941, however, that the U.S. banned oil exports to Japan. This move is seen as key in Japan's attack on Pearl Harbor, Hawaii, on December 7, 1941, "a date which will live in infamy," according to U.S. President Franklin D. Roosevelt as he announced that America would enter World War II. After nearly a decade of militarization, Japan was better prepared for war and enjoyed a series of early victories, driving the American and British Empire forces out of Malaya and the Philippines, almost as far as India and Australia. The Pacific theater was noted for its vicious fighting, often from island to island in terrible conditions.
With Japan's Emperor Hirohito regarded as a deity by his military government, calls for an unconditional surrender following Germany's defeat in Europe in May 1945 were rejected. Both sides continued to suffer terrible casualties until President Harry S. Truman approved the use, on August 6, of the Atomic bomb on Hiroshima. An estimated 80,000 people were killed, yet still Japan refused surrender terms. On August 9, Nagasaki was the target of a second Atomic bomb, and unconditional surrender followed.
After the war, Japan was placed under international control of the Allies, commaded by General Douglas MacArthur. The occupying forces established democratic government. Japan signed the U.S.-Japanese Security Treaty in 1951, allowing the United States to maintain military bases there. The treaty was amended in 1960, removing some of the American rights in Japan.
Through the 1950s and 1960s, as Japan rebuilt its industrial base, it became an increasingly significant trading partner with America and the rest of the world, aligning itself during the Cold War with the U.S. and the West against the Soviet Union and communist China. The Persian Gulf War (1991) forced the United States to revise its strategy in Asia, and in February 1995 the Nye Initiative was published, defining U.S.-Japanese relations as the key relationship in Asia.
By the 21st century Japan was the fourth-largest market for U.S. agricultural exports. Japan is also a key market for U.S. chemicals, pharmaceuticals, commercial aircraft, nonferrous metals, and scientific supplies. U.S. exports to Japan in 2009 totaled $51.2 billion; U.S. imports from Japan were $195.9 billion. The countries also collaborate within the World Trade Organization, the Organization for Economic Cooperation and Development, the World Bank, and the International Monetary Fund.