This is despite the fact that the area was never really in the hands of Han Chinese but was controlled instead by non-Chinese peoples who lived in northeast Asia and who periodically swept down to declare themselves masters of China. Claims that Russia’s Far East should be Chinese date from the Jin dynasty, established in the 12th century by Jurchens, a non-Chinese people from Manchuria.

The Chinese Communist Party, which rejoiced at the recovery of Hong Kong and Macau at the end of the 1990s as a final victory over the British and the Portuguese, has tried since to narrow the country’s historical grievances to the South China Sea and Taiwan, vowing one day to recover the island — seized by Japan in 1895 and later by Chiang Kai-shek’s Nationalist government — and complete what Beijing calls the “wiping clean” of past humiliations.

Russia, an increasingly close diplomatic partner with China, is almost never ranked in official statements alongside Britain, Japan and other former imperial powers that seized territory by force.

Chinese social media, however, bubble with demands that territory ceded to the Russian Empire in the 19th century not be forgotten. A posting on a popular Chinese internet forum, for example, claimed that the Chinese people “are all in tears” when they see that the “table of unrecovered territory” includes Vladivostok and other lands now controlled by Russia.

Young Chinese, who, unlike older generations, rarely speak any Russian and have no rose-tinted memories of Sino-Soviet friendship in the 1950s, are particularly prone to nationalist fervor. “A new, English-speaking generation of young people with weak or distorted notions of Russian history, culture and politics is forming in China,” lamented a report on relations between the two countries by the Russian International Affairs Council.

Anti-Communist groups like the Falun Gong, a spiritual movement banned by Beijing as an “evil cult,” have also seized on the cause of “lost Chinese territory” in Russia to try, mostly in vain, to rally opposition to the governing party in Beijing.