Russian President Boris Yeltsin, still brushing dust off his shoulders from the Berlin Wall’s collapse, traveled to Beijing in late December 1992 to meet with his Chinese counterparts. Newspaper headlines at the time made much ado about Yeltsin’s decision to cut the visit short, with some speculating he sought to placate concerns of the U.S. Congress – fresh off a Cold War “win” – about a new pan-Asian, anti-American bloc. Others believed it was the inevitable result of decades of animosity between the two Eastern powers, combined with a renewed Chinese anger over Russia’s abandonment of true communist ideals. Whatever the cause, outside observers could agree on what brought the two leaders together: China was expanding and wanted cutting-edge technologies, including military weaponry, and Russia desperately needed cash. The leaders signed accords and held a summit to usher in what the Chinese called "relations of good-neighborliness and friendship and mutually beneficial cooperation."

Russian President Boris Yeltsin in 1991. Andre Durand/AFP/Getty Images

"For the former Soviet Union, China was a potential enemy," Yeltsin said at the time. "But today, for Russia, it is no longer a potential enemy."

The progression of the countries' relationship in the subsequent two decades remains as steady as it is mysterious. China and Russia have learned to lean on one another, sometimes strategically, and sometimes because they require each other to keep the lights on. As Russia continues to meddle in eastern Ukraine, China has been reticent to respond despite its highly publicized interest in investment there last year. The situation is yet another telltale sign that much of this powerful alliance has been forged and maintained deep behind closed doors.

The latest incarnation of Russian and Chinese leadership will meet again this month to potentially finalize details of a critical energy alliance. Such an accord will offer new clues into Russia’s apparent neo-Soviet designs and China’s desires to become a legitimate 21st-century superpower.

Publicly, the relationship could not appear rosier. Chinese Foreign Minister Wang Yi in March said the China-Russia relationship was at "its best period in history," describing it as characterized by trust, support and intense cooperation.

“We’ve never had such trusted relations,” Russian President Vladimir Putin said of the Chinese during a live Q&A last month. “Cooperation with China, including that in international issues, is at unprecedented level[s].”



Diana Soliwon for USNWR

“Best friends” might be an oversimplification, but there are significant reasons for Russia and China to appear as such in front of company. For one, China is reportedly Russia's top trade partner after the 28-nation European Union. Trade turnover between the two countries totaled nearly $90 billion last year, according to Bloomberg, and Russian Deputy Prime Minister Dmitry Rogozin has said the countries are aiming for it to hit $100 billion by 2015.

The driving force behind this partnership is, as one expert called it, a “naturally complementary” relationship, largely founded in energy. China’s booming industrialization leaves it parched for more sources of fuel. An estimate from the U.S. Energy Information Administration predicts China will surpass the U.S. as the world’s largest oil importer this year, and its growth in oil consumption accounted for one-third of the world’s consumption growth last year.

Russia, meanwhile, has a lot of energy to sell. The EIA says it is the world’s second-largest producer of dry natural gas and the third-largest producer of liquid fuels. Energy revenues account for half of the country's budget, but it will have to find new buyers in the near future: Angered over Russia’s intervention in Ukraine, the U.S. has stepped up rhetoric calling on Europe to wean itself off Russian gas in exchange for American and other alternative exports.

“China is the obvious buyer,” says Andrew Kuchins, director of the Russia and Eurasia program at the Washington, D.C.-based Center for Strategic and International Studies. China is and will remain a top trade partner of Russia's, he adds, "virtually as long as one can imagine."

With an eye on the future, Putin will meet President Xi Jinping in China later this month. Only those in the room will truly know what they talk about, but energy will be at the top of the agenda.

“[Putin] is going to try, clearly, to play into his own preferences for marking out a path apart from the U.S," says Jonathan Pollack, a China specialist at the D.C.-based Brookings Institution. “The question is whether the Chinese buy into that.”

Chinese President Xi Jinping, left, and his Russian counterpart Vladimir Putin attend the opening ceremony of the "Year of Chinese Tourism in Russia" on March 22, 2013, in Moscow.

Sergei Ilnitsky/AFP/Getty Images

Experts believe the meeting could end with a historic arrangement if the two countries can finally agree on a set price for the gas China will buy from Russia. Any number released publicly likely won't be the actual figure changing hands, but it will seal the fates of the two nations together for the coming years.

Russia and China have continually built a foundation for future cooperation: A series of negotiations in the mid-2000s regarding territorial disputes led to a final agreement in 2008. They share the world’s sixth-longest international border, and possibilities remain for expanding a Siberian gas pipeline and further bilateral development of Russia’s austere eastern regions.

Such practical reliance on one another will continue to bleed into other areas of cooperation in line with what each country aspires to become. Both China and Russia have upped their militant rhetoric in recent months, while also probing their immediate neighbors for territorial weaknesses. Russia’s occupation of Crimea and the subsequent unrest in Ukraine have dominated headline space since March, but China, too, has raised international concern regarding its aggression in the South China Sea, where its territorial claims have contributed to standoffs and skirmishes with countries like Vietnam and the Philippines.

Diana Soliwon for USNWR

Just this month, the Vietnamese government accused China of deliberately ramming its vessels in the South China Sea, in what Vietnam considers intimidation tactics as China explores deep-sea oil drilling. In November, China set up an aerial defense zone over an island chain in the East China Sea also claimed by Japan. U.S. Secretary of Defense Chuck Hagel warned days later it was "not a wise course of action to take for any country."

Wang, the Chinese foreign minister, has hinted that Russia and China are embracing 2015 as a symbol of their strategic military advancements: Both countries will celebrate the 70th anniversary of victory in Russia’s “World Anti-Fascist War” and China’s “People’s War Against Japanese Aggression.” (Most westerners know the conflict as "World War II.")

The occasion will come amid the countries' continued cooperation on military development and sales. China has been Russia’s second-largest recipient of arms shipments since 2008, accounting for 14 percent of all such exports through last year, according to data compiled by the Stockholm International Peace Research Institute. The shipments comprised more than two-thirds of all the weapons China bought during that time.



Overall, China spent almost $160 billion on its military in 2012 – the latest year for which data is available – up from $106 billion in 2008, according to SIPRI figures. Pentagon planners have been eager to cite China’s military advancement as justification for spending unprecedented amounts on space-age weapons, such as stealth ships and the much-beleaguered Joint Strike Fighter program.

“China is pursuing long-term comprehensive military modernization designed to enable its armed forces to achieve success on a 21st-century battlefield,” National Intelligence Director James Clapper wrote in this year’s “Worldwide Threat Assessment” report to Congress.

Then there’s Ukraine, the breadbasket of the former Soviet Union. A Chinese state-run organization announced last fall it planned to invest roughly $3 billion in a 50-year deal to farm 3 million hectares of land there, from which food would be reaped and eventually shipped back to an increasingly hungry Chinese population. The Ukrainian company handling the deal quickly issued a refutation, saying it was working with the Chinese on a 3,000-hectare irrigation project, with the possibility of expansion in the future. The land in question reportedly is in eastern Ukraine, near where the Russians continue a campaign of destabilization with the ultimate goal, according to U.S. officials, of breaking the country in two.



So is Russia’s intervention in Ukraine fueled by a desire to secure land for China? Or perhaps it was a ploy to eliminate Ukrainian competition in food exports and, lest anyone forget, a massive military weapons industry. Ukraine's military spending has been consistently between $3.8 billion and $4.9 billion since 2008, according to SIPRI.

“Russia has a great project,” says CSIS’ Kuchins of the country's latest moves to retake former Soviet territory, centered around its former powerhouse in Ukraine. “They would certainly want to have back under their control the most important part of the Soviet military-industrial complex outside of Russia.”



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China has walked a very thin line between supporting international calls for stability in Ukraine and upsetting its Russian friends and allies. The country abstained from a U.N. Security Council vote in March denouncing Russia’s actions in Crimea. And just last week, the Chinese Foreign Ministry said it was “deeply worried about the current situation in Ukraine,” scolding both Russia for disrupting the political process and the U.S. for its subsequent sanctions.

“The Ukraine situation is, I think, bothersome to China,” says Brookings’ Pollack. “But Ukraine is far away. I don’t see at this point China having a dog in that fight.”