VERKHNE-BLAGOVESHCHENSK, Russia — The crime scene is a riverbank from which Russian Cossacks drove thousands of Chinese to their death by drowning in the Amur River 120 years ago. On a nearby hill stand a bronze memorial statue and a concrete Orthodox cross.
These memorials are not there to mourn the victims. Instead, they celebrate the Cossacks for their role in securing lands that were once Chinese but, since the middle of the 19th century, have been firmly part of the Russian Far East.
For two countries that revel in bitter memories of suffering at the hands of foreign intruders, the gruesome events on the Amur in 1900 present a ticklish problem. Russia and China now have close economic and political ties, and are bound together by shared wariness of the West and by highly selective memories of their own often fraught pasts.
“We need them and they need us,” said Olga Zalesskaia, a China expert and a dean at the Blagoveshchensk State Pedagogical University. “Now we are cooperating, and it makes no sense to stir up all the painful pages of the past.”
Lately, both countries have been trying to sidestep this past.
Russian officials, unlike President Trump, have studiously avoided calling it the “Chinese virus” while China, which responded with fury to a travel ban imposed by the American president, had no complaints about sweeping restrictions on travel from China imposed by Russia at the same time.
But the past is viewed through a prism even more misted.
A museum of local history and culture in Blagoveshchensk, the capital of Russia’s Amur Region, makes no mention of the thousands of Chinese killed on the river, referring only gingerly to the “military events on the Amur, June-July 1900.”
A big part of the museum’s display space is instead being turned over to exhibits recalling the suffering of Russians in the Great Patriotic War, otherwise known as World War II. It is part of a nationwide preparation for celebrations on May 9, marking the 75th anniversary of the Soviet Union’s victory over fascism in 1945.
A Chinese museum on the other side of the river displays a huge painting that shows Russians driving Chinese into the river. But China takes pains not to rub Russians’ face in the episode: The museum is closed to foreigners.
Victor Zatsepine, a historian of modern Chinese history at the University of Connecticut who has studied the incident, said “the massacre definitely happened.”
But, he said, “there is a big difference in how things appear inside China and how they are presented to foreigners.” He noted the Chinese Communist Party has a long record of massaging memories to suit current political, diplomatic and economic imperatives.
In a study of the massacre, Mr. Zatsepine wrote that the episode was not an accident or the result of wartime confusion — Russia’s preferred view of the tragedy — but “a calculated display of imperial power” shaped by Russian attitudes at the time of “cultural and racial superiority.”
Today China has clear superiority, at least in economics, with brightly lit high-rise towers strung along the Chinese side of the Amur as if to taunt Russia’s dowdy riverside, where many buildings date to the 19th century.
But Beijing no longer uses the past as a weapon against Moscow, as it did when relations between the countries deteriorated in the 1960s, triggering armed clashes along the border.
When Russia is mentioned in connection with past bad behavior it is usually referred to as Tsarist Russia, which keeps the country ruled by Vladimir V. Putin at a safe distance.
The Chinese Communist Party, focused on its rivalry with the United States and its allies, still regularly bludgeons Japan and Western nations over their past colonial aggression. Britain, for example, is constantly assailed for seizing Hong Kong, now back in Chinese hands.
But Hong Kong island is a speck of territory compared with the vast tracts of its land taken — and still held — by Russia. A 2015 report on Russia’s expansion along the Amur River by China’s Ethnic Affairs Commission accused Russia of seizing more than 386,000 square miles of “our country’s territory.”
In Russia, the country recently amended the Constitution to forbid any distortion of “historical truth” about actions taken “in defense of the Fatherland.” And in anticipation of the anniversary of World War II’s end, “We all remember” banners are now being strung up across the country.
But the events of 1900 fall into the category of historical episodes that Moscow would rather forget, like the secret protocol of Russia’s 1939 pact with Adolf Hitler, which carved up Poland and the Baltic between Moscow and Berlin.
And on the banks of the Amur River, memory has mostly given way to amnesia.
“Nobody here remembers what happened in 1900,” said Andrey V. Druzyaka, an associate professor in history at Blagoveshchensk State Pedagogical University.
He described the massacre by drowning as a “terrible and shameful mistake,” but not one that should be dwelled on because that would only open a Pandora’s box of potentially explosive historical grievances.
China’s hold on this vast territory before the Russians arrived was never strong. Most residents were either Indigenous peoples, Manchus or others who did not belong to China’s dominant ethnic group, the Han. They were not absorbed into the Chinese Empire until after the founding of the Manchu-led Qing dynasty in 1644.
When the Qing signed the Treaty of Aigun in 1858, it formally ceded territory on the north bank of the Amur River to Russia.
That treaty, like the 1842 treaty with Britain that ceded control of Hong Kong, used to be denounced by Beijing as “unequal” and therefore illegitimate.
Aleksandr Tyurik, the head of an organization representing Cossacks in the Amur Region, said it was best not to focus on the past because this “gives us nothing for the future.”
The Cossacks who drove Chinese residents into the Amur did not aim to kill them, he said, but were simply trying to secure Russia’s border at a time of turmoil, with the anti-foreign Boxer Rebellion raging in China.
How many Chinese were killed in the events of 1900 is not known, with estimates by historians ranging from 3,000 to 9,000. But there is a consensus that thousands drowned after being forced into the Amur by Cossacks and told to swim back to China in what amounted to an anti-Chinese pogrom.
Mr. Zatsepine’s study of the massacre found that the Cossacks also burned numerous Manchu villages, and that “many Chinese were brutally killed before they were thrown in the water.”
Angelika Zvereva, a curator at the Blagoveshchensk museum, acknowledged that “something bad” happened in 1900 but said she did not know the details. More important to remember, she added, was that once the violence ebbed, many Chinese returned to Blagoveshchensk to live and work.
“One month after the fighting, everything returned to the way it was before,” she said, presenting the massacre as a brief and unfortunate detour in an otherwise harmonious relationship.
China, too, has periodically rewritten its accounts of what took place on the Amur River and of Russia’s expansion into formerly Chinese lands.
When China embraced the Soviet Union as a close ally and fellow communist “older brother” in the 1950s, the events of 1900 were almost never mentioned. This changed when the countries became bitterly estranged in the 1960s; then, the Chinese Communist Party commissioned researchers to interview aging survivors of the massacre and produce denunciations of Russian actions.
Those often vitriolic accounts were later watered down in the 1980s as relations with Russia began to improve. The signing of a border agreement in 1991 and the close relationship forged since by Mr. Putin and China’s leader, Xi Jinping, have muffled them further.
“History is such a tricky thing,” said Mr. Zvereva.