Abstract:We study 5d gauge theories that go in the UV to 6d N = (1, 0) SCFT. We focus on these theories that can be engineered in string theory by brane webs. Given a theory in this class, we propose a method to determine the 6d SCFT it goes to. We also discuss the implication of this to the compactification of the resulting 6d SCFT on a torus to 4d. We test and demonstrate this method with a variety of examples.