Karim DamjiIn ancient times, a castle was the home base of defense for the kingdom it ruled. The approach to the castle was not easily accessible. It was defended by one or more deep moats that deterred enemies and reinforced a stronghold capable of withstanding any number of competitive sieges. Fast forward six or seven centuries, and the concept of defensible moats now also applies to corporations. As noted investor Warren Buffet said, "In business, I look for economic castles protected by unbreachable moats."