"I am obliged to tell the truth to the Japanese youth." Twenty-seven years ago Ms Matsuoka Tamaki gave this promise face-to-face with a survivor of the Nanjing massacre when the Japanese school teacher conducted her first investigation in Nanjing.

Over the 27 years, Ms Tamaki has made more than 80 trips between Japan and Nanjing, collecting testimonies from 300 survivors and 250 Japanese veterans involved in the Nanjing massacre. She has been revealing the truth of the Nanjing massacre to Japanese people via videos, photos, voice recordings and written documents.

She is referred to as the "conscience of the Japanese people" by Chinese people. Ms Tamaki was interviewed by an all-media journalist of Xinhua Daily Group in a condominium in Osaka. Upon review of her 27-year journey of seeking the truth about and introspection of the Nanjing massacre, she put her views straightforwardly: "The Japanese government shows no intention of reflecting upon the Nanjing massacre even when confronted with irrefutable proof. I am still striving to make good on my promise."

"I will get to the truth of the Nanjing massacre"

Wearing light makeup, the 67-year-old short and spectacled Ms Tamaki manages to look both youthful and experienced.

"I came across the phrase ‘Nanjing massacre' in a history lecture during my college days but had not even the slightest clue about the historic facts," she said. After having become a teacher in an elementary school she found that the textbooks were too sketchy about the "Nanjing incident". Matsuoka Tamaki realized that historical facts are not in textbooks but accessible only be her own research and discovery. In 1988, Ms Tamaki came to Nanjing for her first investigation. Survivor of Nanjing massacre Li Xiuying held her hand and said, with eyes moist with tears, "I will never forget that my grandparents and parents were killed by Japanese soldiers in front of my eyes. Please promise me you will tell this truth to the young people in Japan." Ms Tamaki gave her solemn word. She said 27 years had passed yet "I still recall the emotion and tears of that survivor. That promise keeps me moving on."

That was how Ms Tamaki embarked on her journey of truth-seeking and introspection on the Nanjing massacre. She traveled not only to Nanjing, but to East China, North China and Northeast China—places that used to be occupied by Japanese troops, collecting large amounts of evidence of the atrocities committed by Japan in the invasion of China and the massacre.

The "Meishinkai" (Imprinted Heart Society) initiative was led by Ms Tamaki in many places in Japan. The name came from the concept "engraved in bones and imprinted in the heart" and suggested that people should face and remember the historic facts that Japan did wage an invasion of China and slaughtered many civilians in Nanjing.

After retirement, Matsuoka Tamaki devoted all her energy to this "sacred cause". She went to Nanjing every year to attend the memorial ceremony and to convey sympathy to survivors. She revealed the historic truth about the Nanjing massacre to Japanese people and called for deep reflection by the Japanese government via assemblies, publications, producing and broadcasting documentaries.

Out of 250 interviewed veterans, only 3 acknowledged their guilt

The road ahead was tough. There has been continuous harsh criticism from her school, parents and the education committee even when the investigation had just started. Yet she ignored all interference and launched this investigation with its far-reaching influence.

"Nearly 200,000 Japanese soldiers fought in the battle to seize Nanjing; however, for a long time afterwards, none of them stood up and gave a narrative about that history." Ms Tamaki found it hard to explain. In October 1997, Ms Tamaki joined with others to launch a three-day "Nanjing Massacre Hotline" story-collecting activity in Tokyo, Kanazawa, Nagoya, Osaka, Hiroshima and Kumamoto. "We received 130 phone calls and 13 veterans who witnessed the Nanjing massacre sent us material. Finally, we had a breakthrough in seeking the veterans involved."

"The Nanjing massacre is a taboo. Those veterans shut their mouths tightly once they heard of us asking something about Nanjing and even drove me away." Ms Tamaki told the journalist that she had to change her tactics. She made a pretence to visit them and brought some gifts. She began the conversation by talking about the bitterness of war and gradually gained some trust. In one extreme case she visited the house of a veteran more than 20 times before the old man was willing to open up his heart. Ms Tamaki has paid visits to many veterans in Mie, Nara, Gifu, Aichi, Osaka and Kyoto.

"Up until now, we have heard the testimonies of 250 veterans. Among the 10 divisions that invaded Nanjing, we have heard the testimonies of soldiers from Divisions 3, 9, 16 and 6, as well as from the headquarters of the Second Anchorage." These perpetrators depicted such scenes as the Japanese army raking with gunfire civilians along the banks of Yangtze River, driving people into warehouses and burning them to death and seeking out women in the name of conscription. Their words were proof of the Nanjing massacre.

About the same time, Ms Tamaki accelerated her pace of investigation into survivors of the Nanjing massacre and eventually collected testimonies from 300 people. "Testimonies of victims and perpetrators can corroborate each other. There was such astonishment that some of the essential information, such as time and place, in testimonies about slaughter, rape and arson provided by both sides, tallied with each other completely", said Ms Tamaki.

Most unfortunately however, although 250 veterans agreed to be interviewed, not many of them repented about what they had done. And up until now only three of them eventually stood up to offer public apologies, including Mitani Sho.

"The Japanese government does not want to take responsibility for the invasion of China during the war. Therefore, against such a backdrop, the veterans did not feel any pressure of public criticism. They usually found such excuses as "following the orders of their seniors" for the Nanjing massacre, and were unwilling to confess their guilt.