  In the K and Bd systems, indirect CP violation is quantified by the
parameters epsilon_K and sin 2beta respectively. Within the Standard Model, the
uniqueness of the CP violating phase implies that the measurement of either
between epsilon_K and sin 2beta permits to predict the other. Since both these
parameters are very well measured, this turns into a powerful test of
consistency. I discuss the status of this test, especially in the light of
recent advances on the epsilon_K formula.
