BERLIN (Reuters) - Two years in age separate Vladimir Putin, the German-speaking former KGB agent who spent five years in Dresden in East Germany's twilight years, from Angela Merkel, the Russian-speaking physicist who grew up near East Berlin.
But familiarity with each other's languages and countries, and a common childhood experience east of the Iron Curtain, have never produced close personal relations.
Now these look poised for a new chill.
Putin's return as president six months ago and his crackdown on dissent are fuelling calls in Germany to adopt a more critical stance towards Moscow and for Merkel to demonstrate this when she visits the 60-year-old Russian this month.
On Friday, lawmakers from the German chancellor's center-right coalition will present a motion insisting that Berlin voice its alarm at recent developments in Russia, urge greater democracy, and champion the rights of imprisoned anti-Putin campaigners such as punk group Pussy Riot.
"Parliament notes with mounting concern that, since President Vladimir Putin's return to office, legislative and judicial measures are being taken which combine towards increasing control over active citizens, criminalizing critical engagement and creating a confrontation course against government critics," a copy seen by Reuters reads.
Raising such issues could play well at home for Merkel, who faces an election next year. Forty-one percent of Germans see Russia as "not democratic at all", and another 45 percent as "not particularly democratic", according to a February survey.
The fate of protesters has been closely followed in Germany, home to 200,000 Russian citizens and 2.5 million ethnic Germans who immigrated from the former Soviet Union.
The resolution increases pressure on Merkel to take a tougher line, but she will be wary of alienating a man who bristles at being lectured and on whom Berlin is reliant.
Germany receives 40 percent of its gas and 30 percent of its oil from Russia, making it gas monopoly Gazprom's largest energy buyer. German investments in the country total $30 billion and it is Russia's biggest trading partner.
"We have to have a pragmatic approach. Russia is on the right path, but in the areas where there are problems, such as human rights and justice, we need to point this out," said Karl-Georg Wellmann, a lawmaker from Merkel's Christian Democrats and an election observer in Russia for the presidential vote.
Germany has been disappointed both by Putin and his predecessor, Dmitry Medvedev, in whom it placed great hopes.
When it became clear last year that Putin would return to the presidency after four years as prime minister, Berlin pushed quietly for him to free imprisoned former oligarch Mikhail Khodorkovsky as symbolic gesture, only to be ignored.
It also pressed for leniency towards Pussy Riot members who incurred Putin's wrath by staging a protest against him in a Moscow cathedral. Instead band members were sentenced to jail terms in Soviet-style prison camps.
Russia's support for Syrian President Bashar al-Assad has also been a source of tension.
Germany has pursued strong business ties with Russia, hoping that, in addition to economic advantages, constructive engagement would empower citizens and foster democracy.
Many Germans feel that failed. In Transparency International's 2011 corruption perceptions index, Russia slid to 143rd place out of 182 countries, tied with Nigeria.
"German-Russian relations are in transition," said Stefan Meister, from the German Council on Foreign Relations.
"The idea that Germany could encourage transformation through engagement is changing. Now there is more criticism and there are those in Merkel's party who want to take a harsher tone."
One of those is Andreas Schockenhoff. A spokesman on Russian affairs for the government and an author of the motion, he has been attacked by the Russian Foreign Office, which is refusing to recognize him as a representative of the German government. This earned a rebuke from the Chancellery.
Schockenhoff is due to chair discussions on civil society at the Petersburg Dialogue, an annual German-Russian conference taking place in Moscow at the same time as Merkel's visit.
"The Schockenhoff case certainly doesn't improve the relationship between Putin and Merkel. There has never been much love or friendship between them," said Fyodor Lukyanov, foreign policy analyst and editor of Russia in Global Affairs journal.
On a visit by Merkel in 2007, Putin reportedly used his large black dog to intimidate the German leader, who was bitten as a child and is believed to have a fear of the animals.
But Lukyanov said relations between the countries are not based on personalities.
"There may be momentary fluctuations - and we are now at a low point - but business interests usually win," he said.
Merkel's predecessor, Social Democrat Chancellor Gerhard Schroeder, cultivated a hearty, macho rapport with Putin, famously referring to him as a "flawless democrat". Schroeder now works as chairman of Gazprom's Nord Stream gas pipeline from Russia to Germany. He has adopted two children from Russia.
German industry voices hopes of empowering Russia's emerging middle classes and exploiting domestic markets.
It remains a constant partner for Russia, even when political ties come under strain - a message reinforced by Putin himself last month in a video message to German industry barons at a gala dinner in Berlin.
"You have pragmatic views, free from illusion or prejudice. You judge today's Russia objectively, you know only too well our untapped potential and reserves," Putin said.
Additional reporting by Andreas Rinke in Berlin and Nastassia Astrasheuskaya in Moscow; Editing by Noah Barkin and Robin Pomeroy