A Witness of Unit 731: The Life and Redemption of Yoshio Shinozuka

by Jenny Chan

Unit 731, a secretive arm of the Imperial Japanese Army, disguised as an "Epidemic Prevention and Water Purification Department," orchestrated some of the most grotesque human experiments in history. Amid the laboratories of occupied Manchuria, thousands—mostly Chinese civilians and prisoners—suffered vivisections, pathogen infections, and chemical tortures in the name of biological warfare. Yet, from this abyss emerged unlikely voices of atonement. One such voice belonged to Yoshio Shinozuka, a teenage conscript whose life became a haunting bridge between perpetrator and penitent.

Born on November 1, 1923, in Chiba Prefecture, Japan, Shinozuka entered the world as the second of five children in a modest family.[1] Growing up in the shadow of Japan's militarizing society, his early years mirrored those of countless boys: elementary school in his hometown, followed by enrollment in a vocational school in April 1938. But the era's relentless drumbeat of conscription interrupted this normalcy. Just a year later, in March 1939—at the tender age of 15—he withdrew from school and passed a rudimentary exam to join the Kwantung Army's Epidemic Prevention and Water Supply Department, better known as Unit 731.[2] Recruited by Captain Tsuchida Mitsu of the unit's aviation branch, who enticed Chiba youths with promises of health officer training and university scholarships, Shinozuka was swept into a nightmare he could scarcely comprehend.
Shinozuka's indoctrination began swiftly. For two months, he studied bacteriology, microbiology, immunology, serology, anatomy, and pathology at the Army Medical School's Epidemic Prevention Research Unit in Ushiku, Tokyo.[3] In May 1939, at 16, he was dispatched to Harbin, China, the frozen heart of Unit 731's operations in Pingfang district. As a junior "youth team" member—essentially child labor for the war machine—he started with menial tasks: caring for bacterial samples, culturing plague and anthrax under fluorescent lights. His job was to raise fleas and ensure they had live rats to feed on.[4] The unit, led by the infamous General Shiro Ishii, masqueraded as a public health outfit while dissecting live humans without anesthesia, testing frostbite by submerging limbs in icy water, and unleashing fleas infected with bubonic plague on villages. By October 1942, Shinozuka's role had darkened. He participated in vivisection on Chinese civilians. His work was to see how the plague that he developed in Pingfang reacts in people’s bodies.[5] Through training, he was officially drafted into the military and served various roles with the Kwantung Army. Shinozuka was a lance corporal with a medical unit near the border with Korea when the war ended in 1945.[6]
Japan's capitulation in August 1945 didn't bring freedom. Stationed in northeastern China to "maintain peace" during the handover, Shinozuka was arrested in February 1946 by Chinese Communist partisans near Tonghua. Mistaking him for a standard Army medic, they pressed him into service: training their medics and lecturing at Tianjin Medical University. For seven years, he lived this double life, haunted by secrets. In 1953, unable to bear the facade, he confessed to his ties to Unit 731. The revelation shattered his fragile cover; he was transferred to the Fushun War Criminals Management Center in Liaoning Province, a grim reeducation camp for Japanese POWs.
There, in isolation, the poison of his past seeped in. Stripped of military bravado, Shinozuka confronted the human cost: the screams echoing in Pingfang's halls, the casual disposal of "maruta" (logs, the dehumanizing slang for test subjects). Released in June 1956 after ideological "reform," he returned to Japan a changed man—silent for decades, wrestling with guilt in Yokaichi City's quiet streets.
The 1980s marked a turning point for Shinozuka. In 1984, at 61, he broke his silence, publicly apologizing for his role in Unit 731's barbarities. Joining the Association of Returnees from China, he became a fixture at peace forums, his frail frame belying a resolve forged in regret. "The other reason I've decided to speak out is that what really happened with Unit 731 had to be made public so that it will never be repeated," he told interviewers.
His most searing moment came in 1997. Testifying for 180 Chinese plaintiffs suing the Japanese government for compensation and an apology, Shinozuka laid bare the unit's sins: the plague cultures, the vivisections, the rivers poisoned with cholera. "I was a member of Unit 731," he declared in court, his words a thunderclap in Tokyo's staid district court, "and I have done what no human being should ever do." The suit, though ultimately unsuccessful—Japan's courts acknowledged the "immense suffering" but denied liability—cracked open national denial, forcing textbooks to acknowledge the existence of Unit 731.
Yet redemption's path twisted cruelly. In June 1998, Shinozuka boarded a flight for a "Testimony Tour" to peace conferences in the U.S. and Canada, invited by groups honoring Nanjing Massacre victims. At Chicago's O'Hare International Airport, U.S. immigration officials—citing a 1996 "watch list" of suspected war criminals—denied him entry, deporting him on the next plane. "It's appropriate that my name be on the list," he had once said, but the irony stung: barred from atoning abroad for crimes committed in youth. Sponsors decried it as a "miscarriage of law," arguing his tour sought healing, not harm.
Undeterred, Shinozuka persisted. He authored books for schoolchildren, warning of war's dehumanizing lure, and revisited Harbin's memorials, laying flowers for the slain. Even in 2002, as a Japanese court affirmed Unit 731's inhumanity, he stood firm: "If you admit that you have done something wrong, you apologize."[8]

1. “Yoshio Shinozuka,” World War II Database, accessed October 9, 2025, https://ww2db.com/person_bio.php?person_id=1092.
   
2. “Yoshio Shinozuka,” Unit 731, accessed October 9, 2025, https://unit731.org/yoshio-shinozuka/.
   
3. “Unit 731: Japan’s Secret Biological Warfare in World War II,” Wayback Machine, archived September 15, 2024, https://archive.ph/tTfda.
   
4. Mark Magnier, “Japanese Veteran Testifies to Unit 731’s Crimes,” Los Angeles Times, September 19, 2004, https://www.latimes.com/archives/la-xpm-2004-sep-19-adfg-poison19-story.html.
   
5. Ibid.
   
6. Yoshio Shinozuka, testimony, Fushun Detention Center.
   
7. “Yoshio Shinozuka,” World War II Database, accessed October 9, 2025, https://ww2db.com/person_bio.php?person_id=1092.
   
8. G. Cameron Hurst III, “Japan’s Germ Warfare: The U.S. Cover-up of a War Crime,” Rense.com, October 18, 2002, https://rense.com/general27/japan.htm.