  We show that long-period dwarf novae offer a promising route for making Type
Ia supernovae. For typical dwarf nova duty cycles d ~ 0.1 - 0.01, mass is
accreted by the white dwarf mainly during dwarf nova outbursts at rates
allowing steady nuclear burning of most of the accreted matter. Mass gains up
to ~ 0.4 Msun are possible in this way. Although these are too small to allow a
0.7 Msun WD to reach the Chandrasekhar mass, they are sufficient if the WD grew
to ~ 1 Msun in a previous episode of thermal-timescale mass transfer, i.e. for
those long-period dwarf novae which descend from supersoft binaries. A further
advantage of this picture is that the supernova always occurs in a binary of
small secondary/primary mass ratio, with the secondary having very little
remaining hydrogen. Both features greatly reduce the possibility of hydrogen
contamination of the supernova ejecta.
