TOKYO - Japan is sending 100 soldiers and radar to its westernmost outpost, a tropical island off Taiwan, in a deployment that risks angering China, with ties between Asia's biggest economies already hurt by a dispute over nearby islands they both claim.

Japanese Defence Minister Itsunori Onodera will break ground today for a military lookout station on Yonaguni, which is home to 1,500 people and just 150km from the disputed Japanese-held islands also claimed by China.

The mini-militarisation of Yonaguni - now defended by two police officers - is part of a long-standing plan to improve defence and surveillance in Japan's far-flung frontier.

Building the radar base on the island, which is much closer to China than to Japan's main islands, could extend Japanese monitoring to the Chinese mainland and track Chinese ships and aircraft circling the disputed crags, called the Senkaku by Japan and the Diaoyu by China.

"We decided to deploy a Ground Self-Defence Force unit on Yonaguni Island as a part of our effort to strengthen the surveillance over the south-western region," Mr Onodera said this week.

"We are staunchly determined to protect Yonaguni Island, a part of the precious Japanese territory."

The 30 sq km backwater - known for strong rice liquor, cattle, sugar cane and scuba diving - may seem an unlikely place for Prime Minister Shinzo Abe to put boots on the ground.

But Yonaguni marks the confluence of the Japanese defence establishment's concerns about the vulnerability of the country's thousands of islands and the perceived threat from China.

The new base "should give Japan the ability to expand surveillance to near the Chinese mainland", said Dr Heigo Sato, a professor at Takushoku University and a former researcher at the defence ministry's National Institute for Defence Studies.

"It will allow early warning of missiles and supplement the monitoring of Chinese military movements."

Japan does not specify an enemy when discussing its strategy to defend its remote islands. But it makes no secret that it perceives China generally as a threat - a giant flexing its growing muscle and becoming an Asian military power to rival Japan's ally, the United States, in the region.

Japan, in National Defence Programme Guidelines issued in December, expressed "great concern" over China's rapid military build-up, opaque security goals, its "attempts to change the status quo by coercion" at sea and in the air, and such "dangerous activities" as last year's announcement of an air defence identification zone.

Yonaguni, at the western tip of Japan's 3,300km south-western island chain, is practically within sight of the disputed rocks that are the feared flashpoint of Japan's island strategy, which could draw the US into a fight.

Mr Onodera's ground-breaking ceremony comes four days before US President Barack Obama lands in Tokyo for a summit with Mr Abe, the first state visit by a US president in 18 years.

The people of Yonaguni, where Mr Abe wants to station 100 troops and perhaps as many family members within two years, have mixed feelings about their imminent role in facing off against China.

"Opinion is split down the middle," Mr Tetsuo Funamichi, the head of the island's branch of the Japan Agricultural Association, said by telephone.

"It's good for the economy if they come, but some people worry that we could be attacked in an emergency."

REUTERS