A Tokyo court acknowledged for the first time Tuesday that Japan had used germs as weapons before and during World War II, slaughtering thousands of Chinese civilians.
But, to the fury of many of the victims and their families, the court rejected claims for compensation on the grounds that all reparations issues have been settled by international peace treaties.
The public gallery was packed with people holding photographs of the dead as Koji Iwata, the presiding judge of the Tokyo District Court, said the Imperial Army had violated the Geneva and The Hague conventions by spreading plague, typhoid, and other diseases in Quzhou, Ningbo, and Changde between 1940 and 1942.
"The evidence shows that Japanese troops, including Unit 731 and others, used bacteriological weapons on the orders of the Imperial Army's headquarters, and that many local residents died," he said.
His terse judgment ended a five-year case, filed by 180 plaintiffs, mostly Chinese, who were seeking both an apology and $83,500 each in damages for the suffering caused by Unit 731.
Although the claims for an apology and compensation were rejected, the legal confirmation of the germ-warfare program was hailed as a breakthrough by the Chinese victims' lawyers.
"The court's recognition of the facts will make it impossible for bureaucrats and politicians to deny what happened ever again," said Kohken Tsuchiya, the head of the plaintiffs' legal team.
For decades after the war, Japanese school textbooks omitted any reference to Unit 731. Until a decade ago, the Japanese government refused even to acknowledge its existence. Even now, it refuses to comment on the unit's activities.
In their ruling, the three judges of the Tokyo District Court said they had little doubt that numerous outbreaks of deadly pathogens in Manchuria were caused by Unit 731's facility at Harbin, set up in 1938 by Gen. Shiro Ishii under the innocuous name of the Epidemic Prevention and Water Supply Unit. "Its main purpose was to research, develop and produce biological weapons," said the ruling. "In order to do this, prisoners from the Chinese resistance forces were used as the subjects for experiments."
During the five-year court case, Unit 731 veterans confessed to carrying out vivisections on humans; cultivating anthrax, typhoid, cholera, and other viruses; and dropping plague-infected fleas over villages.
Elderly plaintiffs flew in from China and testified often in tears - about their communities being ravaged by diseases that spread mysteriously after Japanese war planes had flown low overhead and dropped wheat, rice, or cotton infested with fleas.
After the war, the Japanese Army burned most of the facilities used by Unit 731. The US granted immunity to Gen. Ishii and his colleagues in return for their research findings, and their activities were not mentioned during the Tokyo War Crimes Tribunal.
Historians estimate that the death toll from Japanese biological weapons may be as high 300,000.
Many plaintiffs voiced anger that their compensation claims were rejected.
"I'm furious," said Chen Zhifa, who saw his father and elder brother die in agony after the plague struck their home in Yiwu, in eastern Zhejiang Province. "Biological weapons aren't like ordinary bombs. The impact grows and so does the suffering long after the first attack. But today, the judge dismissed our claims in five minutes."
The plaintiffs said they will appeal, but precedent suggests they have little chance of success. Japan's courts have rejected all of the dozen or so previous lawsuits filed against the government by plaintiffs such as former "comfort women," who were forced into sexual slavery, or POWs.