Though japan's imperial system is thousands of years old, japanese emperors had very little power during the 17th, 18th, and 19th centuries. in 1867, a series of events known as the meiji restoration returned control of japan to its emperor. powerful japanese emperors led a modernization program in japan that allowed it to become wealthy and powerful during the 20th century. the japanese empire used its military power to conquer korea, vietnam, parts of china, and other territories in southeast asia during this period. during world war ii, japan fought as one of the axis powers but was forced to surrender after the united states dropped two atomic bombs on japanese cities. though the united states considered ending the imperial system entirely, it eventually allowed the emperor to remain in place. however, his power was greatly reduced, and present-day japanese emperors serve ceremonial roles instead of being political leaders.