Abstract An analysis is presented of a model for CP violation due to Kobayashi and Maskawa, which has six quarks and purely left-handed currents. The model can reproduce approximately results of the Glashow, Iliopoulos and Maiani four-quark model in CP conserving processes. It gives a close approximation to superweak predictions for CP violation in common K decays, whatever the masses of the fifth and sixth quarks. In principle there are substantial deviations from superweak predictions in rare K decays, but these seem difficult to observe in practice. There are also deviations from superweak results for CP violation in charmed particle decays. The neutron electric dipole moment is very sensitive to the masses of the b and t quarks, lying in a range containing the superweak prediction.