  A new class of enhanced non-perturbative corrections to the inclusive
B->X_s+gamma decay rate is identified, which contribute first at order
Lambda/m_b in the heavy-quark expansion and cannot be described using a local
operator product expansion. Instead, these effects are described in terms of
hadronic matrix elements of non-local operators with component fields separated
by light-like distances. They contribute to the high-energy part of the
photon-energy spectrum but do not reduce to local operators when an integral
over energy is taken to obtain the total inclusive decay rate. The dominant
corrections depend on the flavor of the B-meson spectator quark and are
described by tri-local four-quark operators. Their contribution is estimated
using the vacuum insertion approximation. The corresponding uncertainty in the
total decay rate is found to be at the few percent level. This new effect
accounts for the leading contribution to the rate difference between B^- and
B^0 mesons.
