Six at the top means:

The wall falls back into the moat.
Use no army now.
Make your commands known within your own town.
Perseverance brings humiliation.

The change alluded to in the middle of the hexagram has begun to take place. The wall of the town sinks back into the moat from which it was dug. The hour of doom is at hand. When matters have come to this pass, we should submit to fate and not try to stave it off by violent resistance. The one recourse left us is to hold our own within our intimate circle. Should we persevere in trying to resist the evil in the usual way, our collapse would only be more complete, and humiliation would be the result.