The Chinese are out in force in Red Square; clustered in front of the waggling red flags of their tour guides all over Alexander Garden; shoulder-to-shoulder spanning the breadth of the metro exit, eliciting muttered deprecations from stern-faced Russian commuters; and posing for selfies in front of the gilded onion domes of St Basil’s Cathedral.

But several minutes west, tourists are nowhere to be seen. They are absent from Borovitskaya Square, where the formidable iron likeness of St Vladimir stands guard, and limited to the odd solo traveller in and around the Cathedral of Christ the Saviour and the galleries on Volkhonka Street. Few, if any, notice the unassuming building next to the Pushkin State Museum of Fine Arts. Yet Volkhonka Mansion played a pivotal role in modern Chinese history, hosting not one but two future leaders contemporaneously in the late 1920s.

The mansion dates from the late 17th century, when a stone construction was erected on land owned by the Naryshkins, a boyar family maternally related to Peter the Great. They lent their name to a style of baroque architecture of which the mansion was an example. The estate became a retreat for Catherine the Great before housing the First Moscow Gymnasium, a celebrated high school whose alumni included Russian playwright Alexander Ostrovsky and Bolshevik Nikolai Bukharin, who would renew his association with the building as head of the Communist International (Comintern) organisation, from 1926 to 1929.

By the late 19th century, the main build­ing had assumed its current form, the four-columned Corinthian portico replaced with a simpler metal canopy perched on poles and corbels. Over this summer, the gaudy blue hoardings of Conmebol, the governing body of South American football, have rendered this invisible. The organisation has rented the building for the duration of the 2018 Fifa World Cup, held in Russia. An empty five-a-side kick-about pitch sits in the shade of the lime trees out front. In the lobby, the wide cast-iron staircase, which replaced the original wood structures, is flanked by images of Latin football legends. On the first floor, a Conmebol official stalks across the large function room, stopping momentarily to engage this interloper.

“There are no Chinese here,” he says, brow furrowed in bewilderment. “Oh … I have no idea about the history.”

The white stucco ceiling is dominated by a large chandelier, encircled by neoclassical reliefs in octagonal frames. A border of similarly flowery motifs runs the perimeter of the ceiling’s main space, while elaborate scroll-shaped consoles brace the edges with the walls. Two mezzanine balconies, decorated with ribbon patterns, run down both sides. The current interior dates from the 1950s, when such grand flourishes were a fixture of Stalinist design.

At the far end is a small, nondescript stage, with the Soviet hammer and sickle moulding above it oddly at ease with the more florid decorations surrounding it. In May 1927, Joseph Stalin stood at the podium, attempting to woo an overwhelmingly Trotskyite gathering of young Chinese in what was then the assembly hall of the Comintern-founded Sun Yat-sen Communist University of the Toilers of China (Sunovka). The audience of would-be revolutionaries comprised members of both the Kuomintang (KMT) – which was then nominally the ruling party of China – and the Chinese Communist Party (CCP).

Heckling greeted Stalin’s opening over­tures, visibly perturbing him, although it soon transpired that these hissed impreca­tions were directed at the comical ineptitude of the student interpreter, who was quickly replaced with someone more competent. Though oratorically not a patch on Leon Trotsky, with whom he was then locked in a power struggle, Stalin spoke with commen­dable lucidity, fielding the audience’s – admit­tedly pre­selected – questions in a measured fashion, according to Yueh Sheng, a student who went on to become a member of the CCP’s Central Committee, quitting the party in 1935 and defecting to the United States.

The month before Stalin’s stolid display, a stunning declamation against the “traitor and murderer” Chiang Kai-shek was deli­vered from the same venue, eliciting “thunderous applause”. The speech came in reaction to news of the Shanghai massacre of April 12, which signalled the start of a bloody crackdown against the CCP. Thousands of communists were executed in cities around central and southern China. At Sunovka, as news filtered through, students took to the stage to decry Chiang’s sanctioning of the atrocity, but the most impassioned denunciation came from his own son, Chiang Ching-kuo.

In what must rank among the most filially impious acts in Chinese history, the younger Chiang followed up his broadside with a press statement carried as a front-page splash in all the major Soviet papers.

“Chiang Kai-shek used to be my father and a revolutionary friend,” it read. “He has now become my enemy. A few days ago he died as a revolutionary and arose as a counter-revolutionary … Down with Chiang Kai-shek! Down with the traitor!”

Whether he was pressured into turning on his father is a question that continues to perplex historians, but it seems unlikely. There is evidence that a later letter to his mother in which Ching-kuo further criticised his father, even accusing him of domestic violence, was contrived. A pre-written draft was apparently forced upon him by the CCP representative to the Comintern, Wang Ming, in exchange for the possibility of his return to China. Stalin was seemingly keeping Ching-kuo in Russia as a bargaining chip. Yet, in August 1927, when most of the KMT-affiliated students returned to China following the fallout from the events of April 12, Ching-kuo appears to have made no effort to secure a place on the train back.

In January 1928, just as their figurehead was exiled to Kazakhstan, Ching-kuo re­nounced his involvement with the Sunovka Trotskyite faction. Yet, he would have been well aware that this was no guarantee of absolution. Although he hadn’t got into full swing yet, Stalin had already begun the process that would culminate in the Great Purge (1936-38).

Another indication of Ching-kuo’s commitment to communism was his continued close relations with most of the high-profile CCP students in Moscow, one of whom was to play a key role in the KMT’s eventual defeat in the Chinese civil war. Indeed, indirectly, Deng Xiaoping helped shape the course of his old classmate’s life. His contributions to the eventual communist victory were vital and without them perhaps Ching-kuo might never have ended up in Taiwan, of which Chiang Jnr became presi­dent in 1978. As a political survivor extraordi­naire, Deng, of course, was to eventually ascend to even greater power than his fellow Sunovka alumnus.

As tensions across the strait ratcheted up in the early 1980s, the two leaders did not forget the evenings they had spent strolling along the banks of the Moskva more than half a century prior. Using intermediaries such as Singaporean premier Lee Kuan Yew, they passed on their best wishes to one another. Deng even broached the possibility of a tête-à-tête, which Ching-kuo is said to have politely declined.

On Ching-kuo’s death in 1988, Deng lamented, “It is a pity that he died too early [to see the reunification of China.]”

The pair’s old stomping ground in Moscow is now in private hands for the first time in a century and the mansion is listed in Russia’s cultural heritage register. Administered by the White City Project, an urban regeneration initiative that is committed to its “restoration, preser­vation and revitalisation”, it is home to several local businesses and regularly hosts cultural events and private functions – as well as the occasional tourist curious about the building’s history.

It is hard to imagine the days when the Bolshevik top brass vied for position on stage with a fledgling Chinese political elite that would go on to occupy senior posts on both sides of the Taiwan Strait. Many of these figures would fall by the wayside, leaving their roles in this unlikely tale hidden in the halls of the Volkhonka Mansion.

Getting there

Aeroflot and Hong Kong Airlines fly direct from Hong Kong to Moscow.