On the one hand, there's the relatively small industrial nation in the heart of Europe which - after overcoming Hitler's fascism and the German Democratic Republic - is proud of its democracy and rule of law. On the other hand, there's the single-party state with a population of over one billion people and a huge territory resembling a continent. These two countries, Germany and China, could not be more different. And yet relations between them have developed in a way people never would have imagined 40 years ago.

Proof of that special quality is surely the bilateral talks between the countries' governments. The most recent one saw half of the German cabinet travel to Beijing at the end of August. One year before, the Chinese prime minister traveled with 13 of his ministers to Berlin. Sino-German relations were elevated to a "strategic partnership in global responsibility" in 2004. Over 30 working meetings between experts, ministers, state secretaries and government leaders take place regularly. German and Chinese universities cooperate on over 500 projects, and even exist five joint research institutes exists. There's also an abundance of twinned cities.

To mark this 40th anniversary, the German foreign minister, Guido Westerwelle, has traveled to Beijing. With very few countries does Germany enjoy such an intense exchange.

Trade is the priority

The core of the relationship is expressed in one figure: 140 billion euros ($181 billion). That was the volume of trade between the two countries in 2011. Germany is China's most important trading partner in Europe; Europe is China's biggest trading partner in the world. China is the fifth largest importer of German products, and the second biggest trading partner outside of Europe. German China expert Sebastian Heilmann says economic ties between the two countries have the utmost priority. "Everything else is subordinate to economic relations," he said. "The two countries have a complementary relationship - even today. In other words, Germany supplies things China can use. And China supplies things Germany can use."

A new beginning as early as 1957

As early as 1957, even before diplomatic relations were established, an initial agreement between the Federal Republic of Germany and China was signed - not by the governments, which had no contact, but between the German Committee on Eastern European Economic Relations and the China Council for the Promotion of International Trade (CCPIT). Chief negotiator for the Germans was industrialist Otto Wolff von Amerongen. In an interview with Deutsche Welle before his death in 2007, Amerongen recalled that: "We didn't want the trade relations which had once existed and had of course changed completely due to political developments to completely come to nothing."

Nixon's surprising visit

It was the time of the Cold War. Both Germany and Europe were divided. The United States and the Soviet Union were at a stand-off. At the climax of this conflict in 1972, banking on the logic of the proverb "the enemy of my enemy is my friend," US President Richard Nixon and his Secretary of State, Henry Kissinger, made a surprise trip to Beijing. China, then ruled by Mao Zedong, had had a falling out with its former communist brother-in-arms, the Soviet Union.

For Wolfgang Runge, historian and former German consul in Guangzhou, Nixon's visit to China during the Cultural Revolution was the decisive global political event of 1972. It also had consequences for West German political policy: "At the time, since people were racing to get a foothold in Beijing after the People's Republic of China had taken up China's seat at the UN Security Council in 1971, Bonn could not and did not want to risk being at a disadvantage by not participating in the race."

Mao's man in Bonn

In 1972, Mao sent journalist Wang Shu to Bonn, then West Germany's capital - officially, as a correspondent for the Xinhua news agency. Unofficially, however, Wang was supposed to sound out whether establishing diplomatic relations was possible. Basic agreement was reached quickly, Wang said later, recalling his meeting with Foreign Minister Walter Scheel. "I met with Scheel right away, negotiated for 10 minutes about establishing diplomatic relations - and everything was fine after that." But what followed were 40 days of tough talks over the details of the bilateral agreement. The status of West Berlin was a particularly hard nut to crack. Finally, on October 11, 1972, diplomatic relations were officially established. A trade agreement was signed that same year, but trade remained limited. In 1973, in the year following the creation of diplomatic ties, trade was valued at just one million German marks.

Tiananmen Square massacre

It was Deng Xiaoping's reform policies beginning in 1978 that finally breathed life into the Chinese economy - and into relations with Germany. But 1989 saw the first break in ties when protests by the Chinese democratic movement were quashed by the government on June 4. Relations between Germany and China turned icy, but did not remain that way for long, recalls Runge. "Interestingly, it was only a limited break in ties. There was never a total embargo on trade," he said. "In 1991, trading volume once again reached that of 1988 - the year before Tiananmen Square. One can witness a steady upward economic trend throughout the 1990s."

Kohl's 'Asia Concept'

In 1993, the German government under Helmut Kohl's leadership presented its "Asia Concept," in which the region was described as offering huge potential for the future. German industry was encouraged to invest throughout the continent - especially in China. Sino-German political relations were increasingly used as an instrument to promote trade. German chancellors invariably began to allow large company delegations to accompany them on their trips to China. The success of state visits was often relayed via the number and the size of the economic agreements reached.

And that remains the same today, even if well-established forums for dialogue about rule of law and human rights exist, in which both sides can rub each other the wrong way with their different values.