  The nature of the X(3872) enhancement is analysed in the framework of the
Resonance-Spectrum Expansion, by studying it as a regular $J^{PC}=1^{++}$
charmonium state, though strongly influenced and shifted by open-charm decay
channels. The observed but Okubo-Zweig-Iizuka-forbidden $\rho^0 J/\psi$ and
$\omega J/\psi$ channels are coupled as well, but effectively smeared out by
using complex $\rho^0$ and $\omega$ masses, in order to account for their
physical widths, followed by a rigorous algebraic procedure to restore
unitarity. A very delicate interplay between the $D^0 D^{*0}$, $\rho^0 J/\psi$,
and $\omega J/\psi$ channels is observed. The data clearly suggest that the
X(3872) is a very narrow axial-vector $c\bar{c}$ resonance, with a pole at or
slightly below the $D^0D^{*0}$ threshold.
