Unlike regular enemies, Bosses only show their weak point gauges when they are in a downed state. A boss can be put into a downed state by using either a Focus Spirit Attack or using an item that that Boss is vulnerable to when they are using a specific attack. However some bosses like The Imprisoned and Ganon have specific methods (like destroying The Imprisoned's toes) to put them into a downed state, stunning them and exposing their weak point gauge. In Ganon's Fury, Ganon can put Bosses into a downed state by using specific Boss Attack Items and via Focus Spirit Attack.