Japan will sign a defense pact with Indonesia next week, officials in both governments said, the latest effort by Tokyo to forge closer security ties with Southeast Asian nations and build a counter-balance to China.
Japan has already bolstered partnerships with the Philippines and Vietnam, the two countries most at odds with China over a territorial row in the South China Sea. Japan itself is embroiled in a bitter dispute with China over uninhabited islands in the East China Sea, further to the north.
Indonesian President Joko Widodo visits Tokyo next week for talks with Japanese Prime Minister Shinzo Abe and the two sides will sign an agreement on increasing cooperation in military training and technology, the officials said. Currently, the two countries only have an agreement for the exchange of military students.
Although it will be a non-binding agreement, it is seen as the first step in bolstering defense ties.
The document that will be signed will be on "capacity building, cooperational defense and also peacekeeping operations," said Armanatha Nasir, spokesman for Indonesia's foreign ministry.
Other officials said the two countries could also discuss sharing of intelligence.
A Japanese foreign ministry official said Widodo's trip sends a "big message" as this will be his first state visit outside Southeast Asia.
Japan is supplying maritime patrol boats to Vietnam and the Philippines and will also hold its first naval exercises with the Philippines in the coming months.
For Japan, closer ties with Indonesia could also give its defense firms a better chance to compete against South Korean military equipment makers, who are establishing themselves in the region, a Japanese defense ministry official said.
Widodo will visit China immediately after his stop in Japan. Indonesia and China have a more developed military relationship and Jakarta has bought Chinese-made missiles and other military hardware.
Widodo will bring up the South China Sea issue as part of regional stability talks during his visit to Japan and China, Nasir said.
Indonesia, the largest country in Southeast Asia, has been a self-appointed broker in the myriad territorial disputes between its neighbors and China over the South China Sea.
Tokyo has no territorial claims in the South China Sea, but worries about becoming isolated should China dominate a waterway through which much of Japan's ship-borne trade passes.
The defense cooperation with Southeast Asian nations is also in line with a more muscular security policy advocated by Abe, who wants to loosen the restraints of Japan's pacifist post-war constitution, and dovetails with Washington's "rebalance" toward Asia.