  The $2M$-boson representations of KP hierarchy are constructed in terms of
$M$ mutually independent two-boson KP representations for arbitrary number $M$.
Our construction establishes the multi-boson representations of KP hierarchy as
consistent Poisson reductions of standard KP hierarchy within the $R$-matrix
scheme. As a byproduct we obtain a complete description of any
finitely-many-field formulation of KP hierarchy in terms of Darboux coordinates
with respect to the first Hamiltonian structure. This results in a series of
representations of $\Win1\,$ algebra made out of arbitrary even number of boson
fields.
