In the relative peace of interwar Europe, Finnish architect Otto-Iivari Meurman recorded the discovery of a spiral staircase leading to an underground chamber of the centuries-old Vyborg Castle. But with the outbreak of World War II, the medieval fortress situated in the much-contested town of Vyborg—then under Finnish control, but soon ceded to the Soviets (first at the Russo-Finnish War at the outbreak of the WWII, then wrested once more from Finland in the powerful Soviet offensive of ’44)—had more pressing concerns than the exploration of the subterranean passageway.
As Vyborg navigated the tumultuous years that followed, working to stave off financial woes and creeping disrepair of the castle, which has served as a state museum since 1970, new excavations were put on pause.
The hidden crypt has already yielded two spectacular finds: a purse filled with coins dating to the early 19th-century reign of Russia’s Alexander I and a medieval game board etched into the surface of a clay brick.
According to Katherine Hignett of Newsweek, the board was likely used to play a variation of nine men’s morris, a strategy game that dates back to the Roman Empire and is similar to modern-day checkers.
To play the game, opponents direct their army of nine “men,” each represented by a different game piece, across a grid-like playing field. Erecting a mill, or row of three men, enables a player to capture one of their opponent’s pieces. The first person unable to form a mill, or the first to lose all but two men, forfeits the match.
Alternate versions of nine men’s morris call for each player to rely on an arsenal of three, six or 12 pieces.
Vladimir Tsoi, head of the Vyborg Museum-Reserve, deemed the game board “perhaps the most intriguing find” of the dig, according to the Moscow Times. It’s unclear exactly how old the board is, but a museum press release states that castle records date construction of the underground chamber to around 1561 or 1562.
Late last month, archaeologists unearthed a cobblestone pavement that dates to the 19th century. Just north of this initial discovery, the team identified the remains of a stone parapet dismantled during renovations that occurred between 1891 and 1894. The purse of coins—including 38 two-kopeck pieces dating to 1801 through 1825—was buried below the base of the parapet.
Researchers are still making their way through the shaft, but they believe the "secret" passageway may connect the castle to the city's center. More discoveries are sure to be forthcoming, but for now, you can enjoy the view of the medieval chamber courtesy of virtual 3D model.