What was the motivation of the Japanese attack on Pearl harbor?

Answer 1

The Japanese motives for its attack on the US base and US units in Hawaii (known as the Pearl Harbor attack) on December 7, 1941:

To prevent the US Pacific Fleet & other US Military forces from interfering in the Japanese plans for aggression in China, Dutch East Indies, Malaysia, South Pacific, etc.

The Japanese Navy leaders incorrectly assumed that if they could deliver a 'knock-out punch' against the US battleships & aircraft carriers at Pearl Harbor, then the US government would not have the will power or public support to fight a long & costly war to defeat Japan.

Answer 2

Prior to the attack, Japan was fighting a war against China. The U.S. was exporting scrap steel, rubber, and oil to Japan. The U.S. cut their exports to Japan, which they needed in order to fight China. Japan also allied with Hitler who promised to give them China once he took over the world.

The primary motive for attacking Pearl Harbor was, that the U.S cut exports to Japan infuriating the Japanese.

Answer 3

The Pearl Harbor bombing (codenamed Operation Z by the Japanese) was a preventive attack conducted by the Empire of Japan in order to keep the United States from influencing the war that Japanese leaders were planning in Southeast Asia against Britain and the Netherlands.