Anthony Lovenheim Irwin Rian Thai : International Journal of Thai Studies Vol. 7/2014  Efficacious Space: An Introduction 1 Anthony Lovenheim Irwin 2 1 This paper is derived from the author’s Master’s Thesis: “Imagining Boundaries: SƯma Space, Lineage Trails, and Trans-Regional Theravada Orthodoxy,” (MA Thesis, University of Wisconsin-Madison, 2011). The research for this article was partially funded by the Empowering Network for International Thai Studies (ENITS), Institute of Thai Studies. 2 Anthony Lovenheim Irwin is a PhD Candidate in the Department of Languages and Cultures of Asia at the University of Wisconsin-Madison who has secured Fulbright funding to conduct his PhD dissertation fieldwork in Chiang Rai, Thailand on the subject of new Buddhist building projects in Amphoe Muang Chiang Rai. Abstract Taking into account textual, theoretical, and material evidence, this article makes a case for understanding the power of sƯmƗ space as being linked to the performative and ritual actions of the sangha, as opposed to cosmological or cosmogonic referents. This article uses this specific type of Theravadin spatial arrangement in order to broaden the study of religious space, and to make theoretical room for religious spaces that do not necessarily fit into dominant sacred-space theory. Specifically, this article argues for a new theoretical category of religious space, known as “efficacious space,” which is space that is established according to specific criteria, which by virtue of those criteria, empowers people to effect transformation within that space