By Charles Scanlon
BBC News, Seoul
One South Korean set himself alight in protest
Visitors to South Korea could be forgiven for thinking the country was on the verge of war.
Newspaper headlines accuse Japan of a new invasion for claiming sovereignty over a cluster of disputed islands.
Overwhelmed by fury, protesters have sliced off fingers, set themselves on fire, and in one case committed suicide by jumping off a bridge.
War, of course, is out of the question. Japan and South Korea are close economic partners and have enjoyed much
improved relations in recent years. This year marks the 40th anniversary of diplomatic ties, and there were hopes that memories of Japan's brutal 1910-1945 colonisation of Korea were gradually fading.
Known as Dokdo (Solitary islands) in Korea, Takeshima (Bamboo islands) in Japan
Also known as Liancourt rocks
Japan's and South Korea's claims go back centuries, but islands occupied by S Korea since 1953
Just 230,000 sq m in size, with no fresh water
But surrounding waters valuable for their fishing
But South Koreans are caught up in a spasm of nationalist rage, triggered by what they see as the chutzpah of a former aggressor.
"I can't understand why the Japanese are claiming the islands now when they've been controlled by us for so long. It's as if they want to go back in history and re-colonise Korea," said Park Sung-sok, a local councillor, who came with his colleagues to protest outside the Japanese embassy.
He was with one of scores of groups - from historians to former commandos - who have marched to the Japanese embassy to vent their anger.
"We see it as much more serious than the North Korean nuclear threat," said another protester, Kim Hong-chol, echoing a common sentiment here.
"We're the same people as the North Koreans and we can solve that among ourselves. But Japan is a different country and it's attacked us several times in the past," he said.
The dispute over Dokdo, or Takeshima as the islands are known in Japan, is a perennial irritant to better relations.
The islands are remote and uninhabited, lying about half way between the two countries.
But they sit among rich fishing grounds and there is much talk of potential gas deposits in the area.
The dispute flared up again when the Japanese ambassador to South Korea restated Tokyo's historical and legal claim at a news conference in Seoul.
Korean anger reached fever pitch when the Japanese prefecture of Shimane passed a bill commemorating the centenary of its formal inclusion of the islands in 1905, the same year Japan began to consolidate its colonial rule over the Korean peninsula.
The South Korean government says Japan's moves are seriously damaging friendly relations between the two countries.
"This is not simply a territorial issue, but is nothing short of a denial of the history of our national liberation as well as a justification of past aggression," said the chairman of the National Security council, Chung Dong-young.
South Korea says it will take measures to reinforce its control of the islands, which are currently occupied by a detachment of marine police.
It is also demanding what it calls "genuine reflection and an apology" for Japan's past colonial rule.
The row looks like a big set-back to efforts to promote better regional co-operation and understanding, even though South Korea says it wants to continue to promote friendly ties.
"Relations are very fragile in this region and historical disputes are the toughest challenge we face," says Rhee Jung-ho of the Presidential Committee on Northeast Asian Co-operation.
He was referring not just to relations with Japan, but also to an emotional, historical row with China, which is also seen to be chipping away at Korean sovereignty.
Governments in the region talk much about the need for economic integration and co-operation.
But old rivalries from the past increasingly haunt the present.
The giants in the neighbourhood, China and Japan, are sizing each other up with old scores to settle. South Korea is caught uncomfortably in the middle.