  We propose a novel method of measuring the CKM matrix element V_ub, via
inclusive B decays to "wrong sign" charm. This process is mediated by the quark
level decay b -> u cbar s'. When normalized to the inclusive semileptonic decay
rate, the theoretical expression is very well behaved, with small uncertainties
from unknown quark masses and no leading renormalon ambiguity. We compute the
decay rate for this process, including the leading perturbative and
nonperturbative corrections.
