  The integrability condition of the Ising model is understood as the SU(2)
integrability condition and also as the model parameterized by the elliptic
function, where the integrability condition is understood as the addition
theorem of the elliptic function. The generalization of this integrability
condition is to find the solution of the higher rank Lie group integrability
condition and also to find the model parameterized by higher genus
hyperelliptic function. For the preparation of this purpose, we give the
explicit formula of the addition formula for g = 2 hyperelliptic function.
