  It is shown that there exist nine different ways to describe the flavor
mixing, in terms of three rotation angles and one CP-violating phase, within
the standard electroweak theory of six quarks. For the assignment of the
complex phase there essentially exists a continuum of possibilities, if one
allows the phase to appear in more than four elements of the mixing matrix. If
the phase is restricted to four elements, the phase assignment is uniquely
defined. If one imposes the constraint that the phase disappears in a natural
way in the chiral limit in which the masses of the u and d quarks are turned
off, only three of the nine parametrizations are acceptable. In particular the
``standard'' parametrization advocated by the Particle Data Group is not
permitted. One parametrization, in which the CP-violating phase is restricted
to the light quark sector, stands up as the most favorable description of the
flavor mixing.
