Tuesday’s confrontation between Japanese and Taiwanese coast guard vessels hardly ranks among the great naval battles — the only weapons deployed were water cannon, and the Taiwanese beat a dignified retreat after a few hours.

But the televised maritime contest certainly highlighted the rising passions surrounding the Senkaku islands, a tiny Japanese-controlled archipelago that is also claimed by Taiwan and, more dangerously, by its giant neighbor, China.

Worrying cracks have appeared along a diplomatic fault line that lay mostly quiet for decades, sparking heated talk among international commentators of a possible Sino-Japanese war.

The stakes are certainly high. Japan’s pacifistic constitution may outlaw aggressive war, but in Tokyo there is a firm political consensus that the Senkaku are an integral part of the nation’s territory, to be defended by force if necessary.

But China, which calls the islands the Diaoyu, appears increasingly willing to test Japan’s control by sending state fisheries vessels through their territorial waters.

And the tone and martial language of protests in China this month against Japan’s purchase of three of the islands made clear that some Chinese at least are spoiling for a fight.

Moves by Chinese and Taiwanese state vessels and fishing boats to challenge Japan’s de facto control of the islands could lead to a potentially fatal accident that some analysts say could further escalate hostility from China.

Kunihiko Miyake, research director at the Canon Global Institute in Tokyo, says such an escalation remains unlikely in the near term, given the strength of Japan’s navy — officially known as the Maritime Self-Defense Force — and its alliance with the United States.

While Washington does not take a formal position on who owns the Senkaku, it has repeatedly made clear that it would stand with Japan in the island’s defense.

“China will not use force, because it would lose,” Miyake said.

Instead, he says, Beijing plans to continue using nonmilitary forces to challenge Japan’s control of the group — a strategy in line with the teachings of classical Chinese strategist Sun Zi. “They want to win without fighting,” he said. “This is Sun Zi theory.”

Still, Japanese policymakers are acutely aware that China’s rapid economic growth and the development of its People’s Liberation Army is likely to narrow any current military superiority. On Tuesday, the Chinese navy put its first aircraft carrier into formal service. Development of other Chinese weapons systems such as sophisticated anti-ship missiles poses a potentially even bigger challenge.

Senkaku tensions are likely to strengthen Japan’s determination to refocus its military forces toward stronger defense of southern islands and away from the emphasis on northern ground troops once seen as a bulwark against the Soviet Union.

Under a new defense policy unveiled in 2010, Japan will increase the number of its submarines from 16 to 22, while tank forces — many based on the northern island of Hokkaido — will be cut from 830 tanks to just 400.

The island dispute is also likely to prove a funding windfall for Japan’s already impressively equipped and well-armed coast guard, which has the frontline role in the absence of an overtly military threat.

Candidates in Wednesday’s leadership election of Japan’s Liberal Democratic party, which polls suggest will topple the ruling Democratic party at a general election that must be held by next summer at the latest, have already called for action to beef up the coast guard.

In a set of policy proposals released on Monday, the Japan Institute of International Affairs, a think tank, called for “significant improvements” to the service’s “capacity and equipment” as well as the deployment of more large patrol vessels to the Senkaku area “as a matter of priority.”

The institute also suggested that the tensions might create an opportunity to push the United States to formally endorse Japan’s territorial claim as part of efforts to ensure a “rock-solid” alliance.

Washington is likely to be reluctant to get involved in the sovereignty debate, but the Senkaku tensions have certainly distracted attention from alliance frictions, such as public worries in Japan about the safety of the newly deployed U.S. Osprey tilt-rotor aircraft.

They have also given a boost to those like Miyake who think postwar Japan moved too far to the left and who favor a closer alliance with the United States and more robust defense policy.

“I’m sure China is making a big mistake. The harsher they are and the more assertive, the more they push us to America’s side,” Miyake said. “I personally thank them.”

— Financial Times