  We study the dependence of the Kondo temperature on the gate voltage in a
strongly blockaded quantum dot with a small single-particle level spacing. We
show that the dependence cannot be fitted to that of the Anderson impurity
model with the gate voltage-independent level width. The effect originates in
high-order tunneling processes, which make a dominant contribution to the
exchange amplitude when the gate voltage is tuned away from the middle of the
Coulomb blockade valley.
