Decomposition of Ising spin of spin-S Ising model

We propose a general method by which an Ising spin of a spin-S Ising model is decomposed into Ising spins less than S. Some exactly solvable spin-S Ising models with S greater than 1/2 are obtained without using Horiguchiʹs condition or its extended conditions. These systems are reduced to the Ising model of spin ± 1 or an Ashkin-Teller model.