Kokuy, also known as Kukuy or Kalanch, is a quadrangular blind tower located in the southwestern part of the Novgorod Detinets. It stands out from other towers with its unique shape and height. The tower has a rectangular base measuring 8.5 by 10.4 meters, and its height with the dome is 38.5 meters. The wall thickness at the first level reaches 2 meters, and the tower is topped with a ten-meter tent.

In the 15th century, there was a low tower at the site of the current tower, comparable in height to the walls, similar to the one above the water gates on the river side of the Kremlin. In the 17th century, during the construction of the Voivodesky courtyard complex designed by S.L. Efimov, the tower was significantly rebuilt. It was raised with three rectangular floors, and above that, two more floors were added based on the principle of 'two octagons above a square'. The first two floors with stone vaults housed a wine cellar and a state chamber, while the third floor had exits to the fortress wall, and the top room served for city observation. A wooden tent covered with white iron was installed above the tower, topped with a gilded and partially silvered flag bearing the coat of arms of the Novgorod state, above which was a crown and a flower. After the reconstruction, the tower began to be called Kalanch. The modern name was introduced by P.L. Gusev in 1913. Researchers suggest that the name comes from the Dutch or Low German word 'koke', meaning 'look'. In the 19th century, firefighters from the Sofia part kept pigs and stored cabbage in the lower part of the tower. In 1910, B.K. Rerikh measured the tower. During World War II, the tower housed a German observation post, and by the time the city was liberated in 1944, the upper part of the tower was severely damaged by a direct hit from an aerial bomb. In the 1960s, the tower was restored to its 17th-century forms according to a design by A.V. Vorobyov. Currently, there is an observation deck on the tower, offering views of the Knyazha, Spasskaya, and Dvortsovaya towers. In 2012, two telescopes with 60x magnification were installed on the observation deck.