  Based on a counting scheme for the application of chiral perturbation theory
to pion production in NN collisions p-wave production is studied. It is
demonstrated that, contrary to the s-wave production where loops enter at too
low an order to allow the scheme predictive power, there are certain p-wave
observables where parameter free predictions are possible. These predictions
are consistent with experimental data. We show that the investigation of
charged pion production yields a constraint on a contribution to the
three-nucleon force with a spin-isospin structure that could resolve the $A_y$
puzzle in $nd$ scattering.
