  We discuss the magnetization $M_m$ in the $m$-th column of the zig-zag
layered 2D Ising model on a half-plane using Kadanoff-Ceva fermions and
orthogonal polynomials techniques. Our main result gives an explicit
representation of $M_m$ via $m\times m$ Hankel determinants constructed from
the spectral measure of a certain Jacobi matrix which encodes the interaction
parameters between the columns. We also illustrate our approach by giving short
proofs of the classical Kaufman-Onsager-Yang and McCoy-Wu theorems in the
homogeneous setup and expressing $M_m$ as a Toeplitz+Hankel determinant for the
homogeneous sub-critical model in presence of a boundary magnetic field.
