A battle is underway between China and Japan in cyberspace, with Japanese officials claiming Chinese hackers are routinely attacking websites and Internet services in Japan. Among them is the homepage of the Yasukuni Shrine, a constant source of friction between the two countries.
Japanese officials say cyber-attacks from China have been on the rise for several years.
A particularly intense attack of e-mail barrages on the Internet home of the Yasukuni Shrine in Tokyo forced the web site's closure on January 1.
A shrine spokesman has called the cyber-assault "terrorism" and a malicious challenge to all of Japan.
The Shinto religious institution is dedicated to the souls of Japanese war dead, among them convicted war criminals from the Second World War.
Beijing has repeatedly protested visits by Prime Minister Junichiro Koizumi to Yasukuni, saying the shrine glorifies Japan's military past and its invasion of China in the 1930s and 1940s.
Kuninori So, an analyst at the Cyber Defense Institute in Tokyo says the recent cyber-assault on Yasukuni Shrine appears to have been well organized.
"In this case, for Yasukuni, probably the attack caused by the Chinese hackers should be well organized and a certain amount of groups and people participating," he said.
Mr. So adds the attacks ebb and flow with the state of Beijing-Tokyo relations, and on anniversaries of events that took place during Japan's occupation of China.
Japan plans to set up a special government unit this year to combat cyber-terrorism.
Police here say that while the Chinese attacks are numerous and a nuisance, they are more concerned about the possibility of Islamic militants and North Korean agents using the Internet to take control of or damage critical infrastructure, such as control systems for utilities or banks.