There was chaos on the streets of Nanjing in December 1937 when Japanese troops stormed the Ming dynasty walls of what was then the capital of China, bent on the slaughter still known as the "Rape of Nanking", after the city's former name.
Thousands of residents were killed by the Japanese army, but for some, a saviour was at hand - a member of the Nazi party who offered refuge in the garden of his comfortable, grey-bricked house near the city university and helped save the lives of more than 250,000 people.
John Rabe led a group of Western missionaries, businessmen and scholars in draping Red Cross flags painted on sheets around a two-by-three-kilometre area. The 250,000 people who were able to get inside the safety zone survived - another 300,000 people outside the international safety zone became the victims of the Nanjing massacre.
With his swastika armband, Rabe seems an unlikely or impossible hero, but his courage and the selfless way he administered the safety zone means for many people here he remains the "Living Buddha of Nanjing".
His story is soon to be turned into a Hollywood movie. And Nanjing University is turning Rabe's house into a memorial, with support from his former employer Siemens. It is due to open next month.
The Japanese ground assault began on 10 December and the city fell three days later, signalling the start of the six-week-long "Rape of Nanking". The Chinese say 300,000 people died, although the Japanese insist the figure is lower. Witnesses say Chinese captives were tortured, burnt alive, buried alive, decapitated, bayoneted and shot en masse, and up to 80,000 Chinese women and girls were raped and many more murdered or forced into sex slavery.
The incident has left enormous psychological scars in China and remains a huge stumbling block in relations between Beijing and Tokyo even today.
Rabe's account of the Nanjing massacre in his 1,200-page diary is moving and detailed, and despite being lost for many years, it has become a key historical account of the time.
"If I had not seen it with my own eyes, I would not have believed it. They (Japanese soldiers) smash open windows and doors and take whatever they like ... I watched with my own eyes as they looted the café of our German baker Herr Kiessling," he wrote.
Japan was Germany's ally and Rabe often resorted to waving his swastika armband in the face of a difficult Japanese soldier to try to get his way. The United States was not yet at war, although tensions were emerging and Rabe describes how it was dangerous work and how the foreigners were nearly killed on many occasions. In one case, some Japanese troops broke into the settlement to attack the women.
"We few foreigners couldn't be at all places all the time in order to protect against these atrocities. One was powerless against these monsters who were armed to the teeth and who shot down anyone who tried to defend themselves," Rabe wrote.
There were Chinese soldiers among the refugees and the Japanese forced their way in to arrest them.
"Of the perhaps one thousand disarmed soldiers that we had quartered at the Ministry of Justice, between 400 and 500 were driven from it with their hands tied. We assume they were shot since we later heard several salvoes of machine-gun fire. These events have left us frozen with horror," Rabe wrote.
Fu Bin, from the university's history department, shows me the sections of walled garden where 650 people lived, huddled as refugees in their own city, where Rabe handed out rice and beans.
"Five families lived in the house itself, and many more lived on the grounds," he says.
Fu was one of three historians who went to Germany this year to meet Rabe's grandchildren and others who knew him, to collect relics and files for the museum.
Some of the artefacts held by his grandchildren, who live in Heidelberg and Berlin, are astonishing - beautiful jade necklaces and Chinese dolls. The intimate sepia photographs of this bastion of the German community and his family is a touching testament to expatriate life in the 1930s. But his descendants cherish the memory of what their grandfather did most of all.
The parallels with Oskar Schindler, the entrepreneur who saved the lives of 1,200 Jews, are obvious but Rabe is a more challenging figure in so many ways. He joined the Nazi party early on, was the head of the local branch and does not seem to have doubted his Nazi beliefs.
Tang Daoluan, the director of Nanjing University's archive department, believes Rabe was essentially apolitical and joined the party only to get support for a German school he set up in Nanjing. For her, it was Rabe's humanity that moved her most.
"He is only a businessman, not a priest or a humanitarian worker. What he did here - protecting citizens of another country without regard for his own safety went far beyond his duty. He was a good man who understood human dignity," said Tang.
The son of a sea captain, Rabe was born in Hamburg in 1882 and arrived in China in 1908, joining Siemens two years later. He worked in Beijing until November 1931 when the firm transferred him to its office in Nanjing.
As the company's senior China representative he sold telephones, turbines and electrical equipment to the government.
Photographs show Rabe's ingenuity. An air-raid shelter he built in his courtyard in August 1937, when the Japanese air attack began, was covered with a giant swastika flag to dissuade attackers.
By 1937 it was clear the Japanese were coming, and the foreign community and much of the Nanjing's Chinese population, including the government, evacuated the city in November.
Rabe sent his family home to Germany but he stayed behind with several dozen other foreigners to set up the safety zone. Shortly before the Japanese arrived, Rabe was elected chairman of the 15-member committee of the international safety zone.
"He was reluctant at first and concerned about the safety of his family; but as soon as he took the position, he shouldered the responsibility and didn't turn back," said Tang.
Huang Huiying has written a biography of Rabe and interviewed many survivors.
"Rabe was praised as a living bodhisattva, or living saviour, by those survivors, which is really high praise in Chinese culture," she said.
Even at the time his fame was such that 3,000 women from Jinling Women's University knelt by the roadside in gratitude when Rabe was finally forced to leave the city early in 1938.
After returning to Berlin, Rabe gave lectures about the massacre and tried to get Hitler to intervene. He was arrested and interrogated by the Gestapo for three days and told to shut up. He left for Afghanistan and then went back to Berlin to work for Siemens. After the war, he was de-Nazified and was kept alive by food parcels and money sent from grateful colleagues in China and he died of a stroke in 1950.
But one entry in his diary, around Christmas 1937, sums up his motivation. He had just received a Christmas card, in German and Chinese, from the refugees thanking him for all he had done.
"The best Christmas present I could ever have is to save the lives of over 600 people."Reuse content