Shrugging off disputes that could have wrecked other relationships, the strongmen leaders of Russia and Turkey are pursuing a tight alliance at a time of chilly relations with the West.
Russian President Vladimir Putin meets Turkish counterpart Recep Tayyip Erdogan on Monday in Ankara for talks expected to include foreign policy, more energy cooperation and steps towards a bilateral trade goal of $100 billion a year.
There would be every reason for Russia and Turkey -- the successor states of empires that fought a dozen wars over the last five centuries -- to have testy relations given gaping differences on the key international crises in Syria and Ukraine.
But Erdogan and Putin appear determined not to sacrifice an economic partnership that is critical for both sides, and are working to build stronger relations between the two dominant states of the Black Sea region.
"Both sides have spheres of common interest and they do not want the disputes to get in the way of these," Ilter Turan, professor of political science at Istanbul Bilgi University, told AFP.
- 'Authoritarian personalities' -
Many commentators detect similarities between Erdogan, 60, and Putin, 62 -- both are charismatic men of an almost identical age, leading countries that only came into being in their current incarnation after the collapse of empires in the last century.
Both faced down unprecedented protests -- in Russia in 2011-2012 and in Turkey in 2013 -- to win presidential mandates and the opportunity to continue to lead their countries for the foreseeable future.
And both are accused of harbouring a strong authoritarian streak and are regarded with suspicion by officials in the West.
"There are contextual differences but in terms of having authoritarian personalities I think they may have remarkable similarities," said Turan, emphasising that the Russian political system was more authoritarian than Turkey's parliamentary-based one.
Turkey and Russia would have had every reason for a major falling out in the past few years, especially over Syria, where Putin is the last major ally of President Bashar al-Assad who Erdogan thinks should be ousted without delay.
Ankara meanwhile opposed Russia's annexation of Crimea from Ukraine, and is deeply concerned about the treatment of the Crimean Tatar Turkic minority by the new pro-Kremlin authorities on the Black Sea peninsula.
Yet Erdogan has hardly ever aired Turkey's concerns in public, still less attacked Russia in his sometimes demagogic speeches where he often takes swipes at the West.
A recent joint report by the Istanbul Global Relations Forum and Moscow Carnegie Centre said both countries had "successfully shielded" areas of agreement from areas of dispute.
"The coming years may require a skillful extension of this strategy," the report said.
"Turkey-Russia relations remain stable, maintaining continuity and not depending on the current situation," Putin said in an interview with Turkey's Anatolia news agency ahead of his visit.
On Syria, the rise of Islamic State jihadists has somewhat helped alleviate tensions between Ankara and Moscow, creating a common enemy that both sides can agree on the need to fight.
"In the case of Syria it may be that there is some coming together because, with IS, suddenly there is an element that Russia has as much, if not more, interest in putting down as Turkey," said Turan.
The Carnegie Centre report said the two sides had managed to avoid a "war of words" over Syria. "They have largely managed to compartmentalise their relations" by not allowing the disputes to spoil other areas of cooperation.
- Over-ambitious targets? -
For Turkey, a NATO member which aspires to join the European Union, strong relations with Russia have become a useful bulwark against the risk of a weakening relationship with the West.
But above all, the two sides need each other as partners in energy. Putin noted that in terms of volume, Turkey is the second biggest buyer of Russian natural gas after Germany.
Russia will also build Turkey's first nuclear energy plant at Akkuyu in a project worth $20 billion scheduled to be finished by 2022.
Bilateral trade was $32.7 billion in 2013 while an astonishing 4.3 million Russians visited Turkey in the same year.
But the target to bring trade to $100 billion may prove a step too far, especially at a time of international sanctions against Russia and with Turkey limited in its ability to drastically ramp up exports.
"I think it is a goodwill statement. The intention is there but whether it is easily achievable is open to question," said Turan.