File photo of a wall at the Nanjing Massacre Meseum which indicates approximately 300,000 Chinese civilians and unarmed Chinese soldiers were brutally slaughtered in the massacre. [Photo: Xinhua]

A series of historical files on the investigation into the Nanjing Massacre have been published in China, ahead of the country's Memorial Day for the atrocity.

The files were published by the Nanjing Municipal Archives on Tuesday.

Wang Han, deputy director of the archives, talks about the content of these files.

"The investigation tables have a detailed record for the victims, witnesses and investigators. The methods were professional. The investigation process, witnesses and evidence all have legal sense. These files are the true reflection of what the Japanese soldiers did in Nanjing. They were significant pieces of evidence for the trial of Japanese war criminals, and played an indispensable part in the international war crimes investigation system,"

The invading Japanese troops captured Nanjing on Dec. 13, 1937 and started a bloodbath that lasted for more than 40 days. More than 300,000 Chinese civilians and unarmed soldiers were killed and about 20,000 women were raped.

The 15 published files are part of the documents compiled between July and November 1946.

These documents have been listed in the Memory of the World Register by UNESCO, despite objections and denials from the government of Japan.

Wang Han says the files have been published to restore the history and to make people remember the it.

"We publish the files to safeguard the history,to defend dignity and to respond to the denial of the history by Japanese right-wing forces, and let people in the world to better understand and remember the history, to cherish peace and promote the development of human civilization,"

The files can be viewed on the archives' website as well as on Weibo and WeChat social media accounts.

China will mark the 78th anniversary of the Nanjing Massacre this weekend.