Brandishing imperialist "Rising Sun" flags, the demonstrators gathered at an open air concert hall in the centre of the capital, a chorus of Japan's national anthem serving as an opening ceremony. It was the latest in a series of demonstrations against Beijing's claim to a disputed island chain in the East China Sea, known as Senkaku in Japan and Diaoyu in China. There have also been several anti-Japan rallies in China.
"We have to take action against anyone who is trying to grab our territory," she said at the open air venue, where organisers repeatedly showed footage of the collision on a TV.
Participants then marched through the capital's business and shopping districts near the Imperial Palace, but there were no immediate reports of arrests or any major confusion, police said. The video was leaked on YouTube on Friday. It had not been officially released to the public for fear it would worsen the spat. Japanese authorities have confirmed that the leaked video footage is identical to what the Japan Coast Guard recorded during the incident, the evening edition of the Yomiuri Shimbun reported on Saturday.
In a bid to trace the source of the leak coastguard officials have begun to question the employees responsible for editing and storing the footage, Kyodo news agency reported. The Japanese coastguard arrested the Chinese trawler captain in September for allegedly ramming two of patrol boats near the disputed island chain, sparking a barrage of protests from Beijing.
In Beijing, a Chinese foreign ministry spokesman has again put the blame on Japan for the maritime incident, saying: "The so-called video cannot change the fact and cannot conceal the unlawfulness of the Japanese action."
The latest demonstration comes ahead of an expected visit by Chinese President Hu Jintao to Japan to attend this year's Asia-Pacific Economic Cooperation (APEC) summit, being held in Yokohama near Tokyo.
"We have to tell China ... what we have to say. Otherwise, we cannot maintain our relations of equals," Toshio Tamogami, former chief of staff of Japan's Air Self-Defense Force, told the rally.
"It's time to end the practice of attempting to avoid troubles and put them off," said Tamogami, now head of a conservative lobbying group.
The incident became a flashpoint because both sides claim the potentially resource-rich islets and the nearby seas, as their own, as does Taiwan.
The rally also called on Tibet, Taiwan and China's Uighur minority to form a united front with Japan against the Beijing government. one of the banners posted at the hall read: "Let's condemn China's military hegemony on Asia."
"Japan's sovereignty is in danger," said Yuriko Koike, former defence minister and senior member of the opposition Liberal Democratic Party. "We want to share a sense of crisis with all of you."