Brett’s Question: What did the Japanese hope to gain by attacking the US?
Japan as an island nation required everything to be imported. They had already seized Manchuria and parts of northern China. However, the top Japanese military officials were hopelessly divided; the Army wanted one strategy and the Navy wanted the other. The Japanese wanted the oil and rubber from the Dutch East Indies (Indonesia, Malaysia, etc). They thought to take advantage of the weakened Netherlands under German occupation.
Their main threat: the US Navy.
If and when Japan was to attack and secure those islands, Japan needed time, space to secure its new island acquisitions. By striking at the US at Pearl Harbor, they hope to cripple the USN and force the US to the negotiations table where the Japs could ask the US to accept the new status quo.