“We were never friends.” A massacre on the eve of WWII…

He said he had seen many people on the Japanese internet denying the Nanjing Massacre had happened, including public figures, even politicians. "If we deny it, this will happen again," he continued, urging Japanese people to watch the movies and "Iearn about the dark side of their history".

The video quickly became one of his most popular, with more than 670,000 likes in just two weeks.
But the comments are less positive. The top-liked one quotes what has already become an iconic line from the movie, uttered by a Chinese civilian to a Japanese soldier: "We are not friends. We never were."

Nanjing Photo Studio is the first of several movies this year about the horrors of Japanese occupation
For China, Japan's brutal military campaign and occupation are among the darkest chapters of its past – and the massacre in Nanjing, then the capital, an even deeper wound.
What has made it fester is the belief that Japan has never fully owned up to its atrocities in places it occupied – not just China, but also Korea, what was then Malaya, Philippines, Indonesia.

One of the most painful points of contention involves "comfort women" - the approximately 200,000 women who were raped and forced to work in Japanese military brothels. To this day, the survivors are still fighting for an apology and compensation.

In his video, Kato seems to acknowledge that it's not a subject of conversation in Japan: "Unfortunately these anti-Japanese war movies are not shown in Japan publicly, and Japanese people are not interested to watch them."

When the Japanese Emperor announced on 15 August that he would surrender, his country had already paid a terrible cost – more than 100,000 had been killed in bombing raids on Tokyo, before two atom bombs devastated Hiroshima and Nagasaki.

Japan's defeat, however, was welcomed in large parts of Asia, where the Imperial Japanese Army had claimed millions of lives. For them, 15 August carries both freedom and lingering trauma – in Korea the day is called 'gwangbokjeol', which translates to the return of light.
"While the military war has ended, the history war continues," says Professor Gi-Wook Shin, of Stanford University, explaining the two sides remember those years differently, and those differences add to the tension. While the Chinese see Japanese aggression as a defining, and devastating, moment in their past, Japanese history focuses on its own victimhood - the destruction caused by the atom bombs and post-war recovery.

"People I know in Japan don't really talk about it," says a Chinese man who has been living in Japan for 15 years, and wished to remain anonymous.

"They see it as something in the past, and the country doesn't really commemorate it - because they also view themselves as victims."
He calls himself a patriot, but he says that hasn't made things difficult for him personally because their reluctance to talk about it means they "avoid such sensitive topics".
"Some believe the Japanese army went to help China build a new order - with conflicts occurring in that process. Of course, there are also those who acknowledge that it was, in fact, an invasion."

China fought Japan for eight years, from Manchuria in the north-east to Chongqing in the south-west. Estimates of the Chinese who died range from 10 to 20 million. The Japanese government says around 480,000 of its soldiers died in that time.

Those years have been well-documented in award-winning literature and films – they were also the subject of Nobel laureate Mo Yan's work.

That period is now being revisited under a regime that holds patriotism as central to its ambitions: "national rejuvenation" is how Xi Jinping describes his Chinese dream. While the Party heavily censors its own history, from the Tiananmen Square massacre to more recent crackdowns, it encourages remembering a more distant past – with an outside enemy.
Xi even revised the date the war with Japan started – the Chinese government now counts the first incursions into Manchuria in 1931, which makes it a 14-year war, rather than eight years of full-fledged conflict.

Under him, Beijing has also been commemorating the end of World War Two on a bigger scale. On 3 September, the day Japan formally surrendered, there will be a major military parade in Tiananmen Square.
Also in September, a highly-anticipated new release will focus on the notorious Unit 731, a branch of the Japanese Army that conducted lethal human experiments in occupied Manchuria. The date of release – 18 September – is the day Japan attempted its first invasion of Manchuria.

That is apart from Dongji Rescue, a film inspired by the real-life efforts of Chinese fishermen who saved hundreds of British prisoners of war during Japanese raids; and Mountains and Rivers Bearing Witness, a documentary from a state-owned studio about Chinese resistance.