  We consider the classical instantonic contribution to the open string
configuration associated with three D-branes with relative rotation matrices in
SO(4) which corresponds to the computation of the classical part of the
correlator of three non Abelian twist fields. We write the classical solution
as a sum of a product of two hypergeometric functions. Differently from all the
previous cases with three D-branes, the solution is not holomorphic and
suggests that the classical bosonic string knows when the configuration may be
supersymmetric. We show how this configuration reduces to the standard Abelian
twist field computation. From the phenomenological point of view, the Yukawa
couplings between chiral matter at the intersection in this configuration are
more suppressed with respect to the factorized case in the literature.
