As Germany prepares to welcome Russian Prime Minister Vladimir Putin, the BBC's Berlin correspondent Steven Rosenberg considers how Germany could broker a deal to end the energy dispute between Russia and Ukraine.
Of all the countries in the European Union, it is Germany which has the best relations with Russia. And which, perhaps, is best placed to help negotiate an end to the gas crisis.
The two countries are major trading partners. They are even building a pipeline together - North Stream - which will bring Russian gas to Europe under the Baltic Sea, bypassing Ukraine.
Moscow claims this route will ensure there are no further interruptions to Europe's energy supplies.
Vladimir Putin is best friends with the German chairman of the pipeline consortium - former Chancellor Gerhard Schroeder.
What is more, Mr Putin speaks fluent German from his days as a KGB spy based in Dresden. (Angela Merkel speaks fluent Russian - so no language barrier there.)
But as the energy dispute between Moscow and Kiev drags on, the Germans are growing increasingly frustrated with the Russians.
Vladimir Putin's actions have raised the question of Europe's energy security
Prior to Mr Putin's visit to Berlin, Chancellor Merkel warned the Kremlin its credibility as an energy supplier was on the line. She promised to pass that message on personally to Mr Putin during his visit to Germany.
Embarrassed and annoyed by the images of Europeans shivering without Russian gas, the Germans have been threatening to diversify their energy sources.
"Within the European Union, the subject of energy security is now very important," Guenter Gloser, Germany's minister for Europe, said.
"We need to be independent of those supplying our energy - so we need more energy efficiency, we need more renewable energies like solar projects and we need a range of energy partners - not just Russia."
That is easy to say - and it has been said many times before, not only by Germany, but by other EU countries.
History repeating itself
The last time Russia turned off the gas taps to Ukraine in 2006, causing temporary gas shortages further west, European leaders vowed that never again would they allow energy disputes to the east to leave Europe freezing.
The phrase "energy security" became the rallying cry of the EU.
There were calls to boost solar energy, wind power, and make plans to import liquid gas by sea. Anything to ensure that Europe would not be too dependant on the Russians and get caught out twice.
We didn't learn much from the crisis of 2006
But three years on, it has happened all over the again.
Another dispute between Russia and Ukraine - and once again Europe is freezing. The EU is facing accusations it was too complacent and too divided over European energy policy.
"The usefulness of a crisis is that it forces you to look into the mirror," chief correspondent of Die Welt newspaper Michael Stuermer said.
"That didn't happen. This present crisis could be seen on the radar over the last three months. The signals were coming all the time. I don't think the German government or the EU Commission took note of the seriousness. We didn't learn much from the crisis of 2006."
Micahel Stuermer believes the latest row could nudge the EU to come up with a "coherent energy strategy".
Considering that the European Union currently gets a quarter of its gas from Russia, it is difficult to imagine such a strategy excluding Russia.
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