Why did the Japanese attack Pearl Harbor in Singapore?

Answer 1

First, Pearl Harbor is in Hawaii, USA, not in Singapore, which is at the south end of Malaysia.

Second, the simple answer regarding Pearl Harbor is that the Japanese wanted to deal the US Pacific fleet which used Pearl as its base, a crippling blow, in order to hinder or prevent the US entry into WWII.

The US had embargoed import of oil into Japan on response to Japan's invasion in China. Japan reacted by invading southward into French Indochina (now Vietnam) and Malaysia and Indonesia (controlled by the Dutch and British) to capture the oil fields of those two countries. Since Britain was the main colonial and naval power at the time, with its main base in Singapore, they attacked it within hours of Pearl Harbor (and the Philippines - the other big US base in the Pacific).

Answer 2

Japan launched its surprise attack on Pearl Harbor on December 7, 1941. Japan had wanted to establish its Greater East Asian Co-Prosperity Sphere over the entire Chinese coast, all of Southeast Asia, India, Indonesia, and possibly Australia and New Zealand.

The U.S. embargoed Japan b/c Japan took over Indochina in 1941. The US was also disturbed by Japanese atrocities in China (such as the Rape of Nanjing).

Without steel, oil, and other raw materials from the U.S., the Japanese war effort in Asia would be badly damaged.

Japan saw the embargo as an act of war which caused them to plan the attack on Pearl Harbor.