Short answers, pulled from the story.
The Empire of Japan began on the 3rd of January 1868 when Satsuma-Chōshū forces seized the imperial palace in Kyoto. The empire officially ended in 1947 with the enactment of a new constitution that formed modern Japan.
Crown Prince Mutsuhito became the first emperor of the Meiji era after declaring his restoration to full power on the 4th of January 1868. He succeeded Emperor Kōmei who had died of smallpox in early 1867.
Hard-liners from Satsuma and Chōshū found Tokugawa Yoshinobu's plan for an assembly of daimyōs intolerable and decided to attack Kyoto. This conflict resulted in a decisive victory for combined armies from Chōshū, Tosa, and Satsuma domains at the Battle of Toba, Fushimi.
Japan dispatched the Iwakura Mission in 1871 to gather information on Western social and economic systems which inspired rapid industrialization initiatives. The government recruited more than three thousand Westerners to teach modern science, mathematics, technology, and foreign languages while establishing the yen as the new decimal currency.
Japan formally annexed Korea in August 1910 after winning the Russo-Japanese War from 1904 to 1905. The empire ended its occupation thirty-five years later with the surrender of Japan in World War II.
United States military leader Douglas MacArthur administered the country during the Allied occupation that began after the formalized surrender on the 2nd of September 1945. Reconstruction under this administration continued until 1952 before the Imperial era fully concluded.