Chao In Fort The laterite fortress was built on the southern wall of the city. Between the southwest corner of the fort and the gate. The east side of the fort is next to the Chao In Gate. The layout of the fort is in an arrowhead pentagon. With a pointed end extending into the inner moat With a width extending from the line of the city wall 14.50 meters long, along the city wall 19 meters and a height of about 7.70 meters, the fortress laterite roof sloping up. The top of the fort wall has battlements. And there is a stairway to the fort from the inner city, width 2.70 meters