A fortress draw is a position where the superficially much stronger side can make no progress towards a win, even though there is no threat of him losing anything. E.g. in KQKBN there is the following fortress (which would even hold up to an Amazon):
A fortress draw is a position where the superficially much stronger side can make no progress towards a win, even though there is no threat of him losing anything. E.g. in KQKBN there is the following fortress (which would even hold up to an Amazon):
I guess the simplest fortress is the KPK defense: