This is an ancient shrine which housed the tooth relic during the Polonnaruwa Kingdom. According to the inscriptions on a stone slab next to this building, this building has been built by King Nissanka Malla (1187-1196) to house the tooth relic of Buddha. But it is unclear whether this was built by king Parakramabahu (1153-1186) and was renovated by Nissanka Malla (1187-1196) or whether Nissanka Malla (1187-1196) himself built it. Reason for this doubt is the description of a large relic house built by Parakramabahu (1153-1186) in the chronicles and inability to find this in the Polonnaruwa area. Also King Nissanka Malla (1187-1196) is well known for taking the credit for things others have done by just doing renovation work.
This building is much larger than the Atadage and is surrounded by solid stone walls. In design it is similar to Atadage with two floors. Stone steps to the upper floor are still in place. The upper floor has been probably made out of wood and the tooth relic would have been housed here. On the ground floor remains of three standing Buddha statues can be seen.
“Heta” means sixty and because of this, it is presumed that this building was called by this name because it was completed in sixty days or it housed sixty relics with tooth relic of Buddha.
Another important factor of this building is the Sandakada Pahana (the moon stone) at the entrance. This is a rare instance of a lion appearing on the moon stone. Generally the lion and the bull is not seen in the moonstones in the Polonnaruwa Era.