So what has become of the pacifist movement that grew from a desire to spare others what Japan suffered in 1945?

"I think people are changing. The biggest reason is that their bitter memories of war are fading," said Jiro Yamaguchi, professor of politics at state-funded Hokkaido University.

Many Japanese were asking if it was reasonable not to have a humanitarian presence in Iraq simply because the constitution's Article Nine bans the use of force to settle international disputes, he said.

Since 1992, Japan has contributed internationally by joining UN-led peacekeeping operations, and has extended billions of dollars in aid.

The Japanese still feel they have a debt to pay for being protected by Washington since 1945 even though they have given generous financial backing to other military campaigns under US pressure, he said.

Ken Takada, a member of the secretariat of World Peace Now, a network linking 47 anti-war groups in Japan, said: "Japan has greatly changed -- or entered a phase of transition into a country that can engage in war.

"We have not given up reversing the trend but odds are against us," he said, despite tens of thousands of people taking part in rallies to protest against the Iraq war and sending Japanese troops.

The current anti-war movement draws support from a mixture of unaffiliated individuals, labour unions, hard-line left-wingers and various other groups, activists said.

"Movements by non-organised people have picked up clearly since March last year," said Yasushi Murakami, a steering committee member of Stop War! World Action, which is not part of Takada's network.

"We are upset by the US justification for war ... it is obviously a war of aggression, and Japan was so prompt to support it. I thought I could not accept it," he said.

Murakami and others decided to unite for "a new style" of anti-war movement, since labour unions, once the driving force behind pacifist rallies, are no longer able to attract younger people in the way that they once did.

On the other hand, former radicals, who fought against the government in opposition to Japan's security alliance with the United States in the 1960s and 1970s, "may have become ordinary workers as they had to earn a living," he said.

"But I believe they are still playing a major role in preventing Japan from going down the path to war" by voting for anti-war candidates, Murakami said, adding he had seen such "former radicals" in street rallies.

"Japan's anti-war movements have not swollen into massive demonstrations involving hundreds of thousands of citizens as in Europe but I hope our activity will become a detonator to make more people take action," he said.

Opinion polls have shown that public support has risen for sending troops to Iraq since an advance team of soldiers left here on January 16, but Takada said "Japanese people tend to accept what has already happened."

The January 17-18 poll by the Asahi Shimbun daily found the support had risen to 40 percent from 34 percent last month although about half remained opposed.

Yamaguchi said many Japanese people were concerned about Japan's higher military profile but it "is not the biggest factor" that decides their political stance.

"People are very much afraid that the United States might not protect them (against North Korea) if they anger Americans" by refusing to send troops to Iraq.

WAR.WIRE