Why did Japan attack Pearl Harbor in 1941?

Japan attacked Pearl Harbor in 1941 primarily to secure its imperial ambitions in Asia by neutralizing the United States Pacific Fleet. By the mid-1941, tensions had reached a breaking point as the U.S. severed economic relations, froze Japanese assets, and imposed an embargo on petroleum and other vital war materials in response to Japan’s occupation of Indochina and its ongoing war with China.123

Faced with these restrictions, the Japanese government, led by Prime Minister Tōjō Hideki, believed that seizing resources in Southeast Asia and the Indonesian archipelago was essential for its survival and its vision of a Greater East Asia Co-Prosperity Sphere. Japanese military planners, including Adm. Yamamoto Isoroku, concluded that a preemptive strike on the U.S. fleet would prevent American interference, allowing Japan to conquer the region without opposition. Furthermore, the German invasion of the Soviet Union in June 1941 emboldened Japanese leaders by removing the threat of a Soviet attack from the north, clearing the way for their southern expansion.123