  Using complex notation, we present new simple expressions for two pairs of
complex supercharges in HKT supersymmetric sigma models. The second pair of
supercharges depends on the holomorphic antisymmetric "hypercomplex structure"
tensor which plays the same role for the HKT models as the complex structure
tensor for the Kaehler models. When the Hamiltonian and supercharges commute
with the momenta conjugate to the imaginary parts of the complex coordinates,
one can perform a Hamiltonian reduction. The models thus obtained represent a
special class of quasicomplex sigma models introduced recently by Ivanov and
Smilga.
