Sunday's infraction of that protocol was not the first for China. Just three months prior, two Japanese warships patrolling around Okinawa had discovered an unannounced flotilla of at least 10 Chinese vessels, including two submarines. During the encounter, a Chinese helicopter buzzed one of the Japanese ships, eliciting a formal protest from Tokyo.

These and other recent incidents seem to portray China as a maritime aggressor among nations apparently unprepared to counter any move by Beijing. But Japan, for one, is quietly enhancing military capabilities that themselves pose a serious threat to the fast-growing Chinese navy. Indeed, for all China's rapid naval expansion, the strategic scales in the Pacific still tilt in favor of the U.S. and Japan -- and should continue to do so, provided the ruling Democratic Party of Japan maintains Japan's current course. 

In the last decade, China has accelerated its production of large warships, aiming to replace hundreds of Cold War-era coastal patrol vessels with ships capable of traveling far from shore for extended periods of time. In addition to scores of destroyers, frigates and amphibious assault ships, China is also modifying the incomplete, former Soviet aircraft carrier Varyag for potential operational use. The DF-21 ballistic anti-ship missile, still in development, and associated targeting satellites round out the Chinese naval modernization.

One of China's goals is to exert influence across the planet. Another is to limit rival nations' abilities to project power into Chinese waters. But Beijing is not alone in pursuing a defensive, "anti-access" strategy. Japan, too, is testing supersonic anti-ship missiles that could sink Chinese surface ships. And the island nation already possesses the world's most sophisticated non-nuclear submarines -- a big threat to China's surface and sub-surface forces -- and is bolstering its surveillance capabilities. 

"You could argue that China is building anti-access capabilities to prevent U.S. forces from 'kicking down the door,' but Japan is doing the same thing regarding China," said Eric Wertheim, an independent naval analyst and author of the popular "Combat Fleets of the World." 

Increasingly, the Pacific theater poses dangers to all nations' navies, not just America's or China's. As a result, "we may be entering what may be called the 'post-power projection' era," said Jim Thomas, an analyst at the Washington, D.C.-based Center for a New American Security, at a recent CNAS conference. In coming years, naval strategy could tip the balance of power to the defender. And for all China's fearsome weaponry, this anti-access paradigm probably favors Japan. "It's more inherent in Japanese naval capability to be able do that," Wertheim told World Politics Review. "They're a much more flexible force, much more ready to go."

The very fact that Japan spotted underway Chinese vessels this week and in April highlights Tokyo's ability to monitor, and thus control, regional waters. By combining submarines, aircraft, satellites and surface ships, Wertheim said, the Japanese navy can track Chinese vessels and provide targeting information for Japan's own weapons or for those of its American ally. 

Beyond preparing to deny its own waters to Chinese ships, Japan is also improving its ability to blunt China's own anti-access systems, particularly the much-hyped DF-21 ballistic anti-ship missile. 

"The biggest thing that's been on the minds of anyone is Ballistic Missile Defense and U.S. teamwork," Wertheim said. The Japanese navy's new Kongo-class destroyers, among the most powerful warships in Asia, are fitted with radars and missiles for tracking and shooting down ballistic missiles. The Kongos are used in part to defend the Japanese home islands. But "that BMD capability could also be used to protect U.S. Navy aircraft carriers in the event of hostilities," Wertheim pointed out. 

While Japanese technology is probably up to the task of balancing a rising China, it's less certain whether Tokyo is willing to formalize and deepen its security ties to the U.S. in a way that facilitates bringing that technology to bear. Last month, Japanese Prime Minister Yukio Hatoyama resigned amid public furor after caving in to Washington over the preservation of a U.S. Marine base on Okinawa. Hatoyama had initially sought to relocate the base elsewhere. His successor, Prime Minister Naoto Kan, has carefully sidestepped the base issue since taking office. In the event of a crisis resulting from an incident at sea, for instance, that kind of ambiguous security partnership could undermine military coordination between the U.S. and Japan.

Nicholas Szechenyi, an analyst with the Center for Strategic and International Studies based in Washington, D.C., told World Politics Review that Kan's government is moving in the right direction, albeit slowly. "What we are seeing now, rhetorically, is an emphasis on the critical importance of the U.S.-Japan alliance in countering that [Chinese] threat. Any development will be couched in a bilateral context, perhaps through a strategic dialogue in coming months."

Szechenyi said that it would take time before the details emerge. "But the inclination is going to be engaging in more dialogue with U.S.," he added, "and placing the Chinese threat in a bilateral context."