  We obtain a class of quadratic relations for a q-analogue of multiple zeta
values (qMZV's). In the limit q->1, it turns into Kawashima's relation for
multiple zeta values. As a corollary we find that qMZV's satisfy the linear
relation contained in Kawashima's relation. In the proof we make use of a
q-analogue of Newton series and Bradley's duality formula for finite multiple
harmonic q-series.
