So America stopped exporting essential materials to Japan such as Copper, Iron, and Steel. Hoping that this would deter Japan’s expansion scheme. But this doesn’t happen. In response, America stops selling oil to Japan, Back then, oil was an extremely important resource for Japan. 80% of the oil in Japan was imported from America. America said that they would resume selling oil to Japan only on one condition, they would need to withdraw from the Chinese areas occupied by them, and break their alliance with Germany and Italy.
But doing so would mean the Japanese dream of creating a Greater Asia, would have to be squashed by the Japanese Emperor. Thus they decided to ignore America’s warnings and look for other options. They saw that the areas of Malaysia and Indonesia, were a good producer of oil and other resources. They planned on capturing these areas and drilling for their oil needs. Ending their dependency on America. But there was a problem.
Back then, Indonesia was Dutch East Indies. Under Dutch control. And Malaysia was British Malay. Under British control. British and Dutch both were America’s allies. Even if Japan attacked these countries, it would mean that America might attack them. To defend its allies. There was a chance that America wouldn’t attack. But Japan also planned on capturing the Philippines, which was American territory back then, America had occupied and colonized the Philippines. America would definitely attack Japan then, when they would actively try to steal their territories.