The castle was situated on a small hill, once surrounded by swamps and backwaters of the Liwna River. Difficult to cross terrain surrounded it from the west, south and south-east. The stronghold was accessible only from the eastern side, the outer bailey was also located in that side. In the first half of the fourteenth century, a circumferential wall was erected with a square outline, dimensions of 55 x 58 meters, and a low building in the eastern part. Interestingly, the wall was then equipped with a battlement, which was rare in the Teutonic Order constructions. It was probably erected as a temporary security measure against the Lithuanian threat.
The protracted construction from the second half of the fourteenth century probably resulted in the abandonment of the plan to create a full, four-sided conventual castle. A double-winged layout was created with the main building 55.6 meters long and 14.3 meters wide on the eastern side, covered with a gable roof, supported by the shorter walls on Gothic gables decorated with pyramidal situated blendes. From the side of the courtyard, there was most likely a timber, two-story cloister, providing communication between the floors and rooms. There was a well in the middle of the courtyard.
At the basement level, the eastern range housed two rooms, serving mainly as a warehouse. Both chambers were covered with cross vaults and based on massive brick pillars. The cellars were accessible only from the courtyard side through the necks, i.e. narrow, steep stairs placed in the thickness of the walls. The ground floor was also divided into two parts, separated by a gateway, but their pillars supporting the vaults were made of granite. It had round, very low and wide stems. On the south side, at the gate, there was the doorman’s chamber, and further there was a kitchen with a large hearth and probably a pantry. The northern part of the ground floor was one space. The entire ground floor was lit with small pointed windows. On the representative floor of the east wing there was a four-bay refectory and a four-bay chapel adjacent to it from the north. They were covered with a stellar vault, although it is not certain whether the work was completed. The chapel had a three-side ended chancel, created by thickening and cutting the northern corners of the floor. It was lit from the east with four high, pointed windows and a single window from the north. The last, top floor had a warehouse and defense functions, perhaps there was also an armory there. It was single-space, with a dense row of small openings in the outer walls. The communication between the floors, in addition to the cloister, was provided by stairs in the thickness of the wall between the chapel and the refectory, leading to the top floor.
The northern range of the castle was lower and narrower, and its outer facade was decorated with a series of pointed recesses in which the windows of the first floor were pierced. It was also covered with a gable roof based on a Gothic gable at the west side. This gable has a seven-axis, stepped form, with obliquely positioned pilaster strips passing into pinnacles, between which were made triangular small gables and round wind holes pierced in the upper parts of the pointed blendes. Inside, the north wing had three floors, but did not have basements, moreover, none of the chambers was vaulted. They housed the chambers of the Teutonic pfleger and utility rooms. The former were on the first floor, which was divided into four rooms with access to the latrine on the west side.
In the north-eastern corner, a low, round tower was added at the beginning of the 15th century. Small corridors in a corner buttress led to its small rooms, and from the basement level a corridor led to a dark, damp dungeon. It had quite large niches, perhaps intended for prison cells. The room available from the ground floor has a similar character, it is possible that it was a judicial chamber. At the height of the former chapel, the room could have been the sacristy. The diagonally arranged tower was also planned in the south-east corner, but it was never completed and that is why it is today a giant buttress. In the middle of the courtyard was a well. The whole castle – low and raw – shows a gradual increase of the role of firearms in the fifteenth century and the adaptation of defensive architecture.
