During the two-day tour, Communist Party officials and academics made continuous allusions to the Holocaust. Xu Jingjing, a museum guide, ushered journalists through a dimly-lit exhibit filled with gruesome images of burned and mutilated bodies entitled A Human Holocaust.
"We've looked at the mass massacres, now let's look at the random killings," she said, moving into a room featuring a photograph of a Chinese man who had been decapitated by the Japanese before having a cigarette stuffed into his mouth.
Officials also arranged an interview with an octogenarian survivor of the massacre called Xia Shuqin, who recounted witnessing the Japanese slaughter her family.
"My mother and my little sister were both killed by Japanese soldiers," she said, wiping tears from her eyes with a handkerchief.
"They shot my grandparents. The blood was all over the wall."
Xi Jinping, China's President, is due to visit Germany this month.
There has been no official word as to why Beijing wants to emphasise wartime issues, including a suggested presidential visit to Berlin's Holocaust Memorial.
Relations between Beijing and Tokyo have deteriorated rapidly recently because of escalating frictions over disputed islands in the East China Sea, known in China as the Diaoyu and in Japan as Senkaku, and the toxic legacy of Japan's military exploits in 1930s China.
Japan's leaders have in the past expressed regret for their country's wartime actions in Asia, including a landmark 1995 apology by Tomiichi Murayama, the then-Prime Minister. He sought forgiveness for the "tremendous damage and suffering" caused by Japanese troops in the region.
However, such statements have been undermined by politicians and academics who have played down or denied the Nanjing massacre. Last month, Naoki Hyakuta, a board member of NHK, Japan's state television broadcaster, provoked fury in Beijing by claiming it had "never happened".
A diplomatic source who has been briefed on China's plans for the Xi trip told Reuters that "China wants a strong focus on World War II when Xi visits Germany and Germany is not happy".A second diplomatic source said: "The Holocaust is a no-go area."