The nuclear-powered attack submarine USS Hawaii arrived earlier this month at Yokosuka, home port of the US Seventh Fleet, one more asset in America's naval buildup in Northeast Asia, which can be viewed as a direct result of Chinese assertions of hegemony over the East China and South China Seas.

In July three Ohio-class ballistic missile submarines surfaced more or less simultaneously at Pusan, South Korea, Subic Bay in the Philippines and Diego Garcia in the Indian Ocean. The three are converted Trident missile submarines, having been stripped of their intercontinental ballistic missiles and stuffed with Tomahawk cruise missiles – 140 per sub – armed with conventional warheads.

The Hawaii is part of new class of attack submarines that are configured to operate in shallow, near-shore waters. As the submarine's captain was happy to tell the Pacific Stars and Stripes newspaper on arrival, the sub has the ability to maintain a "persistent presence off shallow waters."

Why would it be important to operate in shallow, near-shore waters? Take out an atlas and trace the string of islands that stretches for more than 1,000 km from the southern tip of Kyushu through Okinawa nearly as far as Taiwan. All are Japanese, although the southern-most is disputed by China.

There is a gap in this island chain between Okinawa and the Japanese island of Miyako known as the Miyako Channel. It is wide enough to provide an avenue of international waters through the island chain and is the principal gateway through which the Chinese navy can pass through on its way to open sea.

The Miyako Channel is becoming one of the most sensitive maritime flashpoints in the world, along with the Malacca Strait, the Strait of Hormuz or the Taiwan Strait. It may be even more sensitive than the Taiwan Strait, as the US and other navies avoid passing through it unless they are trying to be deliberately provocative.

On the other hand, the Miyako Strait is where the US, Chinese and Japanese navies grind together. Last April, a Chinese navy flotilla passed through the channel on the way to open sea. It was shadowed by Japanese destroyers, which in turn, were buzzed by Chinese helicopters, prompting Tokyo to make a formal protest about the harassment of its ships.

Japan is awakening to the fact that their extreme southern flank is basically undefended and open to invasion. For years most of Japan's ground forces were deployed in the northern island of Hokkaido to guard against a Russian invasion. Gradually, Tokyo has been redeploying its troops to the west and south.

This may accelerate as Beijing is becoming more aggressive in asserting its hegemony over nearby waters, not just traditionally recognized territorial waters but the entire South China, East China and Yellow Seas. The Chinese strongly objected to the presence of the aircraft carrier USS George Washington in the Yellow Sea in joint US and South Korean naval exercises. Washington and Seoul moved the maneuvers to the Sea of Japan opposite the east coast of South Korea in deference to Beijing, but the ship may enter the Yellow Sea soon for another series of exercises with the South Korean navy. The South China Morning Post reported Sunday that Tung Chee-hwa, Hong Kong's former chief executive, who remains close to Beijing, called in Adm. Robert F. Willard, the commander of the US Pacific Command and the highest ranking US officer in Asia, to warn against further maneuvers by US carriers in the Yellow Sea.

Currently, China and Japan are embroiled in a growing diplomatic dispute over the southern-most of these islands, which are called the Senkaku by the Japanese and Diaoyu by the Chinese. The two countries dispute ownership. The islands are uninhabited but controlled by the Japanese, whose Coast Guard vessels regularly shoo away intruders.

In a recent incident, The Coast Guard boarded and arrested the crew of one Chinese fishing ship, which it claimed had deliberately rammed their vessels. Tokyo released the crew but still detains the captain. Beijing has protested loudly, postponed meetings aimed at sharing natural gas resources in the East China Sea and cancelled planned diplomatic meetings.

The dispute caught Tokyo at an awkward time as Japan was in the middle of an internal party election to confirm Prime Minister Naoto Kan in office. It will fall into the lap of newly named foreign minister Seiji Maehara, who replaced Katsuya Okada after he was elevated to be the Secretary General of the Democratic Party.

Japan recently extended its ADIZ (Air Defense Identification Zone), where by aircraft entering must identify themselves, further south almost to Taiwan. The government is considering stationing token forces on Miyako and possibly other islands. "Defending strong points in the Sakishima chain (southern-most islands) is very important," said Defense Minister Toshima Kitazawa.

In December the Japanese self defense forces will hold their first-ever maneuvers simulating recapture remote islands from an occupier. The Japanese navy, in turn, is already well-equipped with amphibious assault ships to bring troops to the battlefield if necessary.

There has even been some discussion of creating a Japanese "Marine Corps," although not as an elite independent service as it is in the US The defense ministry would designate a regiment or even a division for special training in Marine Corps-like activities, such as amphibious assaults.

These developments put the presence of the US Marine Expeditionary Force on Okinawa in a new light. Who is better equipped or trained to recapture isolated islands? Former premier Yukio Hatoyama came to recognize the deterrent value of the Marines on Okinawa, although too late to save his job.

His successor as prime minister says his government will honor the agreement with Washington to close the Futenma Marine Air station and build a new base for the Marines at another less crowded location on the island despite continuing political opposition from the island.

Is the threat of China seizing any of these islands by force realistic? One could equally ask how realistic it was to expect the Russians to invade Hokkaido. Militaries plan for contingencies, and who is to say that in the future some Chinese leaders decide that "historical documents" dating back to the Ming Dynasty "prove" that these islands are really Chinese territory and occupy them?