But while China and Russia have much in common, including a mutual fear of separatism and Islamic radicalism, there are also signal differences. Despite last week's exercises, and a visit to Russia by Hu Jintao, the Chinese president, in June, politicians in Moscow harbour a deep-seated fear of China - in particular, of Chinese encroachment.
Russian TV recently claimed that Beijing has drawn up a secret plan. According to this top-secret blueprint, China is determined to grab back Russia's remote, but vast, far east region. China's strategy includes persuading migrants to settle in Russia, marry local women and steal or co-opt local businesses.
Russia's far east has always been the most strategically vulnerable part of Moscow's fissiparous imperium, in what is the world's biggest country. Some 6,100km (3,800 miles) and an eight-hour flight from Moscow, the far east is home to just 6.5 million Russian citizens. Next door, across the Amur river in north-eastern China, there are 107 million Chinese. Given this demographic imbalance, there is a primordial fear in the Russian imagination that China will eventually try to steal back the Europe-sized far east of Russia - a region rich in mineral resources, trees, coal and fish. The salmon alone are an attractive target. A quarter of the world's Pacific salmon spawn in the volcanic Kamchatka peninsula. According to the Russian TV scenario, Beijing is furtively plotting to undo the Russian colonisation of the Pacific coastal region, started in the 18th century by tsarist-era adventurers. The area's original inhabitants were Chinese. These early nomads eked out a meagre living while dodging the tigers that still haunt the Sikhote-Alin mountains.
In reality, the relationship is far more fascinating than the baseless fears of Russia's nationalists. Over the past decade the number of Chinese migrants working in Russia's far east has actually fallen. In Moscow, the authorities have recently shut down the capital's enormous Cherkizovsky market, turfing thousands of Chinese out of a job. The huge bazaar was home to Chinese traders selling billions of dollars-worth of grey-sector goods. (According to China's Xinhua agency, losses from Wenzhou in Zhejiang province alone amount to more than $800m, after Russian police confiscated their stocks.) Some 150 Chinese workers have been deported since the market was closed on 29 June.
Most experts believe China's own strategic goals do not include Russia's far east, or primitive territorial expansion. Instead Beijing's priorities lie elsewhere. They include development, reunification with Taiwan and internal stability, which experts suggest is more of a priority than ever following last month's ethnic riots against Han Chinese in Xinjiang.
According to Dr Bobo Lo, a lecturer on Chinese-Russian relations at the Centre for European Reform, Beijing's real challenge to Moscow is rather different. He argues that the rise of China will lead to the "steady marginalisation of Russia from regional and global decision-making". The Chinese do not want to invade Russia militarily because, he points out, they would lose.
Any loss of influence would alarm the Kremlin, which still sees itself as a major global power. Over the past nine years, under president and then prime minister Vladimir Putin, Russia has worked hard to recover its superpower status. However, few outside Moscow doubt that the main challenge to the United States's increasingly wobbly global and economic hegemony comes not from Putin's Moscow but Hu's Beijing.
"In 1969 China and Russia fought a war over one of these river islands," Udenka explains, sitting in his captain's cabin and steering in the middle of the river. "It was a small war. Now there are good relations between Russia and China. We trust each other," he adds, in broken Chinese.
The problem of what to do with the far east has long exercised Moscow's leadership. The Soviet Union offered generous subsidies to cajole workers and young couples to start a new life here. They got higher salaries, career opportunities, and flats. There were also cheap air fares back to European Russia. The incentives were needed given the region's harsh climate - scorching summers and freezing winters, with January temperatures regularly falling below -30C.
However, after the demise of the Soviet Union this system collapsed. With a ticket to Moscow now costing £500 return, a new generation has grown up with weaker ties to the capital. Instead of visiting St Petersburg, local Russians are more likely to holiday in China - travelling by bus to the Chinese seaside resort of Dalian and other destinations in China's north east.
Gradually, Asiatic Russians are getting to know their neighbours better. Farther down the Amur in the border town of Blagoveshchensk, Russian pensioners have even started buying up apartments on the Chinese side of the river. Other young Russians head west: since the early 1990s the Russian far east's population has plunged by 1.6 million. This exodus is a source of increasing worry for the Kremlin. On Friday Putin travelled to Khabarovsk to unveil a new pipeline stretching from the Russian island of Sakhalin to Khabarovsk and the far eastern port of Vladivostok. The pipeline will take gas to China, Japan and South Korea - part of an attempt to stimulate the region's economy.
In June, during his trip to Russia, Hu attended a summit of the Shanghai Co-operation Organisation, and held talks in Moscow with Russia's president, Dmitry Medvedev, which led to the signing of a massive oil deal. He also had tea with Putin. The deal reinforced China's growing economic influence in the region, and its emergence as a competitor with Russia for Central Asia's energy reserves.
In Khabarovsk, meanwhile, few locals see much prospect of the far east breaking away from Moscow. Despite improved understanding between China and Russia, the cultures remain too different. (The Chinese see the Russians as western-centric.) In Khabarovsk, the last stop on the Trans-Siberian Railway before Vladivostok, nobody is talking about secessionism.
"I've had a few relationships with Russian girls. But I'll end up marrying a Chinese one," says Tsi Ke, 25, who has lived for the past decade in Khabarovsk. Tsi owns a thriving Chinese restaurant, where blonde Russian waitresses wear Chinese dresses. He adds: "In China we believe a wife should stay at home a lot and be like a daughter to your own parents. For us, marriage isn't just between two people but between two families."
A more pressing problem for the Kremlin is the growing estrangement between Russia's western and eastern halves. Resentment of Moscow and its far-away bureaucrats is rising. There have been grassroots protests in Khabarovsk and in Vladivostok after Moscow raised duties on second-hand Japanese cars late last year, killing off a major regional business. Anti-Kremlin protests are continuing.
In May, Medvedev dropped into Khabarovsk for an EU-Russia summit. (The venue - 10 hours' flight from Brussels - was apparently chosen by Russia to punish the EU's pampered representatives, several of whom fell asleep during sessions).
Medvedev flatteringly described the far east as his "favourite part" of Russia, and expressed sympathy with students too broke to travel to Moscow. This summer the Kremlin has introduced a scheme offering some discounted tickets to the under-23s.
It remains to be seen whether the scheme will make much difference. In reality, though, successive governments in Moscow have done little to develop the far east - making the region susceptible to civic unrest and discontent. The region suffers from "long-term neglect by Moscow" and "appalling corruption and misgovernment at regional level", Bobo Lo says.
Despite last week's show of unity during military manoeuvres, the relationship between Beijing and Moscow is no longer one of equals. Russia may see China as an important strategic counterweight to the US - with whom it is currently in conflict over a range of issues, including the planned US missile defence shield in central Europe.
But the Chinese know that it is they, and not Putin's Russia, who are destined to become the world's newest superpower. And according to Bobo Lo, China is not interested in allowing strategic accommodation with Moscow to disrupt Beijing's more important partnership with Washington. "Washington is still the world's only indispensable partner," he notes.
A history of tension
"¢ Throughout much of the cold war Beijing and Moscow were enemies. However, Stalin had encouraged and financed Mao Zedong's revolution, recognising his communist People's Republic in October 1949. The partnership survived Stalin's death and the early Khrushchev years.
"¢ In 1959 the two countries squabbled over which should lead the world communist movement, an ideological quarrel replicated in communist parties across Asia and Africa. Khrushchev's decision to back down during the 1962 Cuban missile crisis also needled Mao.
"¢ In March 1969 tensions exploded when Russia and China fought a brief war in Russia's far east over the disputed Damansky island (now known as Zhenbao), close to Khabarovsk.
"¢ Tensions continued in the 1970s and 1980s, especially after the Soviet invasion of Afghanistan, pictured above. Détente only became possible after the Soviet Union's demise.
"¢ Over the past two decades relations between Beijing and the Russian Federation have improved, with booming trade, agreement on many international issues, and growing military co-operation. In 2004 Russia settled a long-running border dispute with China, handing over Tarabarov island in the Amur river, and half of another large island, Bolshoy Ussuriysky.
"¢ China's rise, however, is likely to place increasing strain on the relationship. Experts believe that, as China becomes a world superpower, Russia's influence will diminish - a fate the Kremlin is unlikely to accept.
