  We have solved exactly the $Osp(1|2)$ spin chain by the Bethe ansatz
approach. Our solution is based on an equivalence between the $Osp(1|2)$ chain
and certain special limit of the Izergin-Korepin vertex model. The completeness
of the Bethe ansatz equations is discussed for a system with four sites and it
is noted the appearance of special string structures. The Bethe ansatz presents
an important phase-factor which distinguishes the even and odd sectors of the
theory. The finite size properties are governed by a conformal field theory
with central charge $c=1$.
