Holomorphic twist of an N=1 SQFT is defined by restricting to the cohomology of one supercharge, capturing the quarter-BPS operators that are counted by the supersymmetric index. The twisted theory is endowed with extra structures and symmetries which are a 4d analogue of a 2d chiral algebra. In this talk, I will focus on the example of the holomorphic twist of pure SU(N) gauge theory. We observe that the differential in the holomorphic twist receives loop corrections which make the theory topological. This can be interpreted as a sign of confinement of the original theory. I will also present a holographic realization of the holomorphic theory in the topological B-model. The talk is based on joint work with Davide Gaiotto, Justin Kulp, Brian Williams, Jingxiang Wu and Matthew Yu.