A stance is a unique state that grants use of new moves. In exchange it may limit access to blocking, movement or even portions of your normal movelist. Some stances, like Eddy's Negativa or Anna's Chaos Judgement, also have evasive or autoparry properties. A stance might be entered freely, have optional entry only from certain moves, or mandatory entry only from certain moves, depending on the character. Or a blend of all three properties.