  The critical line of the Riemann zeta function is studied from a new
viewpoint. It is found that the ratio between the zeta function at any zero and
the corresponding one at a conjugate point has a certain phase and its absolute
value is unity. This fact is valid along the whole critical line and only
there. The common functional equation is used with the aid of the function
ratio between any zero and its negative side pair, a complex conjugate. As a
result, an equation is obtained for solving the phase along the critical line.
