General self-cousistency conditions are derived for N* j == 1 /2 production ampKtu-* des and coupling constants by tbe methods of püre S-matrix theory. The similarity to electroproduction is discussed. We consider N(kt) + ^(k^) ->■ N*(k3) -{-^(kt) (1) reaction (s-channel) with masses k^^ = m = m'32 ’ and k^ = N and N* are both spin 1 {2, isospin 1 /2 nucleon resonanees. The spin basis for the reaction (1) is well known from electroproduction, only a slight modification is needed to take çare of the unequal masses of the nucleons: