  We modify the Sakai-Sugimoto model of chiral symmetry breaking to take into
account the open string tachyon which stretches between the flavour D8-branes
and anti D8-branes. There are several reasons of consistency for doing this:
(i) Even if it might be reasonable to ignore the tachyon in the ultraviolet
where the flavour branes and antibranes are well separated and the tachyon is
small, it is likely to condense and acquire large values in the infrared where
the branes meet. This takes the system far away from the perturbatively stable
minimum of the Sakai-Sugimoto model; (ii) The bifundamental coupling of the
tachyon to fermions of opposite chirality makes it a suitable candidate for the
quark mass and chiral condensate parameters. We show that the modified
Sakai-Sugimoto model with the tachyon present has a classical solution
satisfying all the desired consistency properties. In this solution chiral
symmetry breaking coincides with tachyon condensation. We identify the
parameters corresponding to the quark mass and the chiral condensate and also
briefly discuss the mesonic spectra.
