Hot Spring Door
It is the second gate that directly enters the city from the main gates of Bursa walls. The gate is the only gate of Bursa Castle opening to the west. It was named "Thermal Spring Gate" because it is on the road leading to the thermal springs in Kükürtlü and Çekirge.

The Kaplıca Gate has a corbelled type, protected by city walls, in line with the defensive strategy seen in the walls of Bursa. Additionally, the door is an entrance door protected by an L-plan scheme.

Only the opening of the door has survived to the present day.