The Chinese military is conducting air and sea drills in the contested region, prompting concern from neighbours Japan and Taiwan.
Japanese Prime Minister Shinzo Abe is in Hawaii for a visit to Pearl Harbor, the US naval base attacked by the Japanese in 1941.
He's laid a wreath at a cemetery remembering those who died in the attack in 1941.
That attack sparked America's entry into World War Two and the beginning of the War in the Pacific.
But a far newer confrontation is possible.
In a show of force, Chinese warplanes have flown over the Miyako Strait, a patch of sea close to Japanese territory.
Japan's defence ministry says six Chinese vessels, including an aircraft carrier, were seen travelling between Miyako and Okinawa into the Pacific Ocean.
A patrol helicopter took off from one of the ships and flew close to Miyako, prompting Japanese fighter jets to scramble.
Chinese state television has released pictures of the mid-air standoff, describing the Japanese intercept as a dangerous interruption to a legal military exercise.
Japanese Chief Cabinet Secretary Yoshihide Suga says the drills are an unprecedented step.
"It's the first time the Japanese Self-Defence Force confirmed China's aircraft carrier entering the Pacific Ocean. We've been alerted, as this represents a expansion of China's maritime force."
But Hua Chunying, a spokeswoman for the Chinese Foreign Ministry, says the drills are part of an annual plan.
"As you mentioned, some countries are paying a lot of attention to this drill. I think there is no need to read too much into it, such as whether it was targeting anyone."
The ships also passed through waters 90 nautical miles from the southernmost point of Taiwan, which China considers part of its territory.
The exercises come amid renewed tension over the island, following US president-elect Donald Trump's controversial phone call with the Taiwanese president.
Jean Jonathan Bogais is a specialist on conflict in South East Asia at the University of Sydney.
He says it is likely there is another motive for China's move.
"It is a way for China to tell Donald Trump's administration, or future administration, 'we are not going to compromise on the One China policy.'"
