- The game, carved into a hunk of clay, is likely a version of nine men's morris
- It is believed the game, similar to checkers, has been played for centuries
- Archaeologists said the board game is the 'most intriguing' find so far from Vyborg Castle
A medieval board game has been discovered in a secret chamber hidden underneath a 13th Century Russian castle.
The game, carved into a hunk of ancient clay, is likely a version of nine men's morris, a strategy game that sees players battle with small pieces known as 'men.'
It is believed the game, which is similar to checkers, has been around for centuries and was popular in the Roman Empire.
Russian archaeologists said the newly uncovered board game is their 'most intriguing' find so far as they continue excavations at Vyborg Castle.
A medieval board game (pictured) has been discovered in a secret chamber hidden underneath a 13th Century Russian castle
First records of the fortress, built on a small island in the Bay of Vyborg, date back to 1293.
Located near the Russian-Finnish border, the structure has changed hands between the nations several times over its history and is currently under Russian control.
Records dating back to the mid-16th century mention a 'secret house' with a staircase that leads to the shore.
Last month researchers uncovered an underground chamber that had remained hidden for centuries.
A 3D model suggests that the chamber probably linked the castle to the city of Vyborg city which is at the head of Vyborg Bay.
While looking inside the chamber, archaeologists from Vyborg museum discovered what they initially thought was a clay brick and later discovered was an ancient game.
The game is believed to have been called tablei - which translates to 'mill'.
In it, each player aims to claim the other player's men.
It is a popular game that dates back to the Roman empire and is sometimes also known as 'cowboy checkers'.
Researchers uncovered an underground chamber last month at the 600-year-old fortress that had remained hidden for centuries. Pictured is the game they found
Russian archaeologists said the newly uncovered board game is their 'most intriguing' find so far as they continue excavations at Vyborg Castle (pictured)
When a player gets a 'mill' - which is a row of three men - they get a piece from their opponent.
When one player is down to just two men they game ends as they are no longer able to make a 'mill'.
'This is perhaps the most intriguing find at the moment [at the site],' head of the Vyborg museum-reserve Vladimir Tsoi wrote on his Vkontakte social media page.
Archaeologists were looking at the site as early as 1935.
According to the architect Otto-Iivari Meurman who was working on the site back then, experts saw 'that a spiral staircase was leaving the ground'.
However, efforts to excavate the site were subsequently abandoned.
Over the years the building has been neglected, with many concerned the castle was falling into ruin.
However, a 1.8 billion-ruble fund (over $25 million/ £19m) has now been set up to restore Vyborg castle.