I will talk about a solution to the inverse problem for Ising models on reduced planar graphs in a disk, i.e., recovering the edge coupling constants from the boundary spin correlations. A recursive solution to this problem was provided by Galashin-Pylyavskyy. The solution I will present is non-recursive. It is based on an Ising model analog of the chamber ansatz which asserts that the inverse map should factor through variables on the graph that transform under the Ising Y-Δ move according to the discrete CKP equation. This is joint work with Terrence George.