Last year Xi became the first Chinese president to attend an official ceremony to mark the anniversary of the incident, delivering a speech saying that China would fight any attempt to sanitise the history of Japan’s aggression in apparent criticism of Japanese Prime Minister Shinzo Abe.

Although the Chinese government is ramping up its denunciations of Japan’s past militarism, Beijing’s relations with Tokyo have markedly improved from a year ago, with increased high-level political contacts taking place in recent months following Xi’s two meetings with Abe.

A skirmish between Japanese and Chinese troops near the bridge on July 7, 1937 developed into full-scale warfare that lasted until Japan’s surrender to the Allied Powers in 1945.

This year’s ceremony at the Museum of the War of Chinese People’s Resistance Against Japanese Aggression, near the bridge on the outskirts of Beijing, was attended by Liu Yunshan, the Communist Party’s fifth-ranked leader.

Liu was there to open an exhibition called “Great Victory, Historical Contribution” at the museum featuring 1,170 photographs and 2,834 historical relics, which shows that the Communists played an important role in securing victory.

Speaking in front of armed forces personnel, children and veterans, propaganda chief Liu said people should draw inspiration from the “splendid annals” of the war.

“We must use this platform and classroom to guide officials and the people to draw sustenance from the hard struggles of the past,” said Liu

 Liu said Japan was responsible for the incident that led to its invasion of China, adding that the exhibition was important for the second world war anniversary and Beijing’s patriotic education.

The exhibition highlights some of the horrors of war, including a skull from a person killed in the 1937 Nanjing Massacre and a spiked metal cage used to torture captured Chinese.

Another picture shows a woman raped by Japanese soldiers and then disembowelled and dumped on the road.

Almost all the exhibits have English translations, underscoring the government’s desire to get its message about Japanese brutality and Communist bravery to a worldwide audience.

The Communist Party’s role is in sharp focus  –  exhibit captions are peppered with references to the reluctance or refusal of the Nationalist Chinese government to fight Japan. 

In China’s official narrative the contribution of Nationalist troops  – who later fled to Taiwan after loosing a civil war with the Communists in 1949 – is barely mentioned.

In actuality, China’s war with Japan was fought mainly by the Nationalist forces under then President Chiang Kai-shek, which withdrew to Taiwan from the mainland at the end of a civil war with the Communists in 1949.

Last weekend, Taiwan’s President Ma Ying-jeou said it was Nationalist Chinese forces who won the war, decrying attempts to “distort”  history.

“Our exhibition clearly shows that our Communist Party was the cornerstone in the war to oppose Japanese aggression, and we have a lot facts here to show that,” deputy museum director Luo Cunkang told reporters, when asked about the Taiwan comments.

The highlight of China’s 70th anniversary activities will be a major military parade to be held on September 3 in Tiananmen Square.

Xi will oversee the parade and deliver a speech on the day which is regarded by China as its victory day of what Beijing calls the eight-year war of resistance against Japanese aggression.

Outside China, the forthcoming commemorations are seen as the Communist Party’s part of efforts to legitimise its one-party rule.

Additional reporting by Reuters