Philippine President Ferdinand Marcos Jr arrives in Japan on Wednesday for a visit that is expected to pave the way for closer security ties with Tokyo, as Manila increasingly sides with the US in its regional tussle with China.
Marcos and Prime Minister Fumio Kishida are expected to deepen cooperation in disaster relief, a possible precursor to establishing a broader legal framework that would allow Japanese forces to deploy to the Philippines more easily.
"As the US deepens its relationship with the Philippines, it's important for regional security that Japan join in," a Japanese defence ministry source with knowledge of internal discussions on national security told Reuters. He asked not to be identified because he is not authorised to talk to the media.
Marcos's first visit to Japan since taking office in July comes after he signed an agreement last week granting the US greater access to its military bases. It also follows a trip to Beijing last month where he told his Chinese counterpart, Xi Jinping, that the Philippines would pursue an independent foreign policy.
At a press briefing last week, Neil Imperial, the Philippines Assistant Secretary for Asian and Pacific Affairs, said Marcos wanted to "facilitate closer defence, security, political, economic and people-to-people ties" while in Japan.
That sentiment is shared in Tokyo, which has been deepening security ties with nations that view China with concern.
A year ago, Japan and Australia signed a visiting forces agreement, allowing them to deploy forces on each other's soil, with Tokyo concluding a similar accord with Britain last month. Those deals provide a framework for how Marcos and Kishida could also forge deeper military ties to counter their common adversary, say experts.
"The Philippines is a critical security partner for Japan," said Narushige Michishita, a professor at the National Graduate Institute for Policy Studies in Tokyo. "Any conflict in the Taiwan Strait would make the Philippine Sea strategically important," he added.
Taiwan, which lies between Japan and the Philippines, has become a focal point of intensifying Chinese military activity that Tokyo and Washington worry could escalate into war as Beijing tries to capture what it views as a rogue province.
A Japanese military presence in the Philippines could also help Marcos counter Chinese influence in the South China Sea, much of which Beijing claims, including territory that Manila considers its own.
Beijing has said its intentions in the region are peaceful.
Marcos has vowed not lose an inch of territory in the strategic waterway, through which US$3 trillion (RM12.9 trillion) in ship-borne trade passes annually.
By gaining access to bases in the Philippines, Japan would extend the range of its defence forces, including surveillance aircraft that could patrol the South China Sea, according to Ken Jinbo, a professor at Keio University in Japan, who also served as a government security advisor.
"One thing people are watching out for during President Marcos' visit, is whether Japan will agree to provide infrastructure assistance now that the US has access to the nine bases there," he said.