[en] The chargino anti χ_1.2^± system can be reconstructed completely in e⁺e^- collisions. By measuring the total cross sections and the asymmetries with polarized beams in e⁺e^- → anti χ_i⁺ anti χ_j^- [i,j = 1,2], the chargino masses and the gaugino-higgsino mixing angles of these states can be determined very accurately. If only the lightest charginos anti χ₁^± are kinematically accessible, transverse beam polarization is needed to determine the mixing angles unambiguously. From these observables the fundamental SUSY parameters can be derived: the SU(2) gaugino mass M₂, the modulus and the cosine of the CP-violating phase of the higgsino mass parameter μ, and tan β = v₂/v₁, the ratio of the vacuum expectation values of the two neutral Higgs doublet fields. [The remaining two-fold ambiguity of the phase can be resolved by measuring the normal polarization of the charginos.] (orig.)