In the winter of 1937, invading Japanese troops captured Nanjing, then the Chinese capital, and over the course of six weeks, they proceeded to kill approximately 300,000 Chinese civilians and unarmed soldiers in one of the most barbaric episodes of World War II.

Amid the massacre, a German businessman named John Rabe continued to keep a diary, and his diaries remain one of the most comprehensive historical records of the atrocities committed by the Japanese aggressors.

Serving as the Siemens representative in China, Rabe helped establish the Nanjing Safety Zone together with other foreign residents. The 3.86-square-km refuge protected around 250,000 Chinese civilians from the massacre.

Christoph Reinhardt, the great-grandson of John Rabe, mourns at the tomb of John Rabe in Berlin, Germany, Aug. 7, 2025. [Photo by Du Zheyu/Xinhua]

Despite the constant peril, Rabe stayed in the city and negotiated repeatedly with the Japanese military to rescue victims and defend the safety zone. At the same time, he documented the atrocities unfolding around him in his diaries.

"I want to witness these atrocities with my own eyes, so that I can later speak of them as an eyewitness. Such brutal crimes -- committed 10 days after the city's capture -- must not be kept silent!" he wrote on Dec. 24, 1937.

On Dec. 14, 1937, the day after Nanjing's fall, Rabe confided in his diary that it was not until he drove through the shattered streets that he grasped the true extent of the destruction.

"Every 100 or 200 meters, we came across corpses. The Japanese marched through the city in groups of 10 to 20 men, looting shops. Had I not seen it with my own eyes, I would not have believed it," reads the diary.

Thomas Rabe holds his grandfather John Rabe's diaries at the John Rabe Communication Center in Heidelberg, Germany, Aug. 7, 2025. [Photo by Zhang Fan/Xinhua]

On another page, he recounted the fate of a boy of about seven, stabbed four times with a bayonet. One gash in his abdomen, Rabe wrote, was "the length of a finger." The child survived for two days in the hospital before dying -- quietly, without a single cry.

"In John Rabe's diary, written by my grandfather, you can read how the members of the Nanjing Safety Zone repeatedly wrote letters to the Japanese embassy in Nanjing at that time, vehemently condemning them and urging them to stop harming and slaughtering Chinese civilians," Thomas Rabe, grandson of John Rabe, told Xinhua. "However, all these efforts were in vain."

"Remembering history is crucial," he said. "Nazi Germany committed the holocaust, a crime against humanity that must never be repeated. After WWII, Germany made peace with its former victims and took responsibility, with Israel, France, Poland, and others. Unfortunately, not all countries have learned from the past."

This photo taken on Aug. 7, 2025 shows the file photo of John Rabe in 1938 at the John Rabe Communication Center in Heidelberg, Germany. [Photo by Zhang Fan/Xinhua]

John Rabe passed away in 1950 and was laid to rest in the western suburbs of Berlin. But the gratitude of the Chinese people has never faded with time.

At his grave, there are always fresh flowers and handwritten notes. One recent message read: "Thank you, Mr. Rabe, the good man of Nanjing. The Chinese people will never forget."