The Bethe/Gauge correspondence of Nekrasov and Shatashvili describes the low energy dynamics of the vacua of certain supersymmetric gauge theories in terms of integrable spin chains. I will discuss an application of this correspondence in solving the spin chain dynamics, in the way of solving the (dynamical) Yang-Baxter equation, using the gauge theory. More specifically, I will discuss the construction of the R-matrix of elliptic superspin chains as mass Janus partition functions of 3d N=2 gauge theories on elliptic curves. The construction is partly motivated by recent developments of a string theoretic perspective on the Bethe/Gauge correspondence.