  In this work we present the $\alpha'$-exact background equations of motion of
the bosonic chiral string (also known as Hohm-Siegel-Zwiebach model), with the
spin two ghost fields integrated out. This is the first instance of a
worldsheet model in which all corrections are fully determined in a generic
curved spacetime. As a concrete cross-check, we find complete agreement between
all three-point and a sample of four-point tree level scattering amplitudes
computed using field theory methods and the chiral string prescription. These
equations of motion provide a field theoretical shortcut to compute worldsheet
correlators in conventional bosonic strings (with arbitrary number of massless
and mass level one states), and outline a new perspective on massive resonances
in string theory.
