Does thebquark decay left-handedly?

The left-handedness of the b quark weak couplings has not yet been tested experimentally. We present an SU(2${)}_{\mathit{L}}$×SU(2${)}_{\mathit{R}}$×U(1) model with purely right-handed b decay couplings. We show that the model is consistent with the quite severe existing experimental constraints from B decays, from ${\mathit{B}}^{0\mathrm{-}}$B¯ ${}_{}{}^0{}_{}{}^{}$ mixing, from the neutral K mass difference, and from CP violation in the kaon system. We point out a difficulty in distinguishing our scheme from the standard model in semileptonic B decays.