  Sh2-188 is thought to be an ancient planetary nebula in the galactic disk. It
appears to be one-sided with recent observations revealing structure behind the
filamentary limb. We postulate that Sh2-188 is interacting with the ISM and
simulate it in terms of a ``triple-wind'' model comprising of the usual
``fast'' and ``slow'' interacting stellar winds plus the wind due to motion
through the ISM. We have run simulations at various velocities of the central
star relative to the ISM and find that a high velocity of 125 km/s best
approximates the observed structure. We also suggest that Sh2-188 is younger
than previously thought and that much of the mass lost on the AGB has been
swept downstream.
