Mr Gul's decision to accept an invitation from Armenia's president, Serzh Sarkisian, has raised expectations that Turkey may establish diplomatic ties and open the border it closed during the 1990s fighting between Armenia and Azerbaijan over Nagorno-Karabakh.

ECONOMIST: Turkey and Armenia

Relations between the two were disrupted 16 years ago over Armenia's occupation of Nagorno-Karabakh, an enclave in Azerbaijan.

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Mr Erdogan declared that friendship with Armenia was no longer possible unless it withdrew from Nagorno-Karabakh.

ECONOMIST: Turkish foreign policy

Azerbaijan fought a war with neighbouring Armenia in the 1990s, in which it lost the Nagorno-Karabakh region, and the two sides may yet fight another.

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Indeed, absent Russian efforts to reduce tensions, Armenia and Azerbaijan would almost certainly have gone to war over Nagorno-Karabakh sometime over the past five or six years.

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Unlike chess-players, though, all the participants can win in this game, it is hoped, if they agree on a common aim: peace between Turkey and Armenia, which would help to thaw the frozen conflict between Armenia and Azerbaijan over the (mainly Armenian) territory of Nagorno-Karabakh.

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