Before 1941, oil from Southeast Asia (specifically Indonesia, then a possession of the Dutch) was Japan’s main energy source.
In 1941 the U.S was able to threaten that oil supply with the U.S. Navy.
On 7 December 1941 Japan struck the U.S. Navy at Pearl Harbor in hopes of eliminating the threat to the Japan oil supply. That attack enabled U.S. President Roosevelt to declare war on Japan, which resulted in the USA entering World War II against Japan and Japan’s allies Germany and Italy.
From 1942 through 1945 the U.S. Navy tried to prevent the transport of fuel and food (especially rice) to Japan by sea. When I first came to Japan in 1964, we still had to buy rice from the government-controlled rice stores.
In 1954 Japan decided to join the nuclear reactors for power club, to avoid having to rely on foreign oil for electric power plants. The first nuclear power plant went online at Tokai in 1966.
In 1960 the US-Japan Security Treaty came into effect, although Okinawa remained under U.S. control until 1973.
In 2011 the nuclear reactor disaster at Fukushima (Japan-311) led to a total reversal of Japan’s energy policy: No more NUCs, return to oil and add LNG, this time from the Persian Gulf, more than twice the distance to Southeast Asia. But also this time, the focus has been on the development of renewable energy sources: solar, wind, hydro, ocean currents, and hydrogen, the earth’s most plentiful element.
Japan must rethink excessive reliance on US security, says expert TOKYO — As the pandemic forces the U.S. to step back from global leadership, Japan has an opportunity to reassess its overreliance on its top ally, according to a leading national security expert.
Pointing to Washington’s decision to withdraw thousands of troops from Germany, Keio University professor Yuichi Hosoya says Tokyo must watch “to what extent the U.S. will continue to remain involved in the defense of Japan, South Korea and Taiwan.”
“It is time for Japan to help itself,” Hosoya says. But he also warns that with China growing its maritime activities, it may require a significant higher financial burden.