Philippine President Benigno Aquino and Japanese Prime Minister Shinzo Abe have agreed to begin talks on weapons trade deals and joint military exercises amid China's increasingly assertive posture in the region's seas.
Yesterday, the two leaders signed a five-page "Joint Declaration on our Strengthened Strategic Partnership" that involves exporting Japanese military hardware and technology to the Philippines to ensure "maritime safety and security in the disputed South China Sea".
In a joint news conference, Mr Abe said he agreed with Mr Aquino to oppose China's "unilateral attempts" to change the status quo in the South China Sea.
"Regarding the South China Sea issue, we've reaffirmed that we are concerned about the large-scale reclamation, and that we are opposed to unilateral attempts to change the status quo," he said.
For his part, Mr Aquino said the joint declaration "affirmed that the strategic partnership between our two countries has entered an enhanced and elevated stage".
With Japan's own territorial dispute with China over islands in the East China Sea, Mr Abe has long criticised China's attempts to change the status quo in the South China Sea by dredging sand to transform reefs in the Spratly archipelago into islands with wider maritime entitlements.
Latest satellite images show that China has so far expanded its holdings in seven Spratly reefs by at least 800ha, with one able to support a 3km-long runway and a harbour for a flotilla of warships.
Although it has no territorial claims in the South China Sea, Japan is worried that China may gain control of international waterways through which significant Japanese trade passes. Over US$5 trillion (S$6.7 trillion) in ship-borne trade passes through the South China Sea every year.
The Philippines, meanwhile, has expressed concern that China may use the islands to force it to abandon 10 islets, reefs, shoals and other rocky outcrops it now occupies in the Spratlys.
China has maintained that the islands, while serving military purposes, are "primarily civilian" in nature and open for use by other nations.
But it also asserts its "indisputable sovereignty" over nearly all 3.5 million sq km of the South China Sea, and reserves its right to declare an air defence identification zone in the region.
Their mutual concerns over China have spurred a deepening alliance between the Philippines and Japan.
Mr Aquino's state visit comes less than a month after the Philippines and Japan held their first joint naval exercise near a Philippine-claimed shoal now under Chinese control.
Japan has so far agreed to hand over 10 new patrol boats for the Philippine Coast Guard.
Prior to meeting Mr Abe, Mr Aquino witnessed a contract signing to seal that deal. The first three boats are expected to be delivered to the Philippines later this year.
The joint declaration signed by Mr Aquino and Mr Abe now opens discussions on the Philippines' request for P-3C anti-submarine reconnaissance aircraft.
Manila is also hoping to acquire Japanese radar kits to help it monitor Chinese activities west of its borders.
This article was first published on June 5, 2015.
Get a copy of The Straits Times or go to straitstimes.com for more stories.