This edifice, featuring 176 stone pillars, has been identified as an Uposathagara or chapter house. An inscription at the Abhayagiriya monastery indicates that King Mahinda V (956-972 AD) renovated a chapter house called "Diyasen" at the Jethavana Monastery, suggesting the existence of an earlier chapter house.
The present structure of the chapter house had several stories, with the upper floors possibly serving as residential quarters for the monks. The ground plan of this chapter house closely resembles that of Rathnaprasadhaya, the chapter house at the Abhayagiriya Monastery. This architectural similarity highlights the standardized design and functional importance of chapter houses in ancient Sri Lankan monastic complexes.
