Subrule · Chapter 3
cr:3.0.4e
If a rule or effect specifies an object in a public zone, the source must be public for the rule or effect to apply unless otherwise stated.
Example: Tome of Torment has the text “You may play this from your banished zone.” If a Tome of Torment is private (face-down) in the banished zone, a public zone, its ability would not apply because it does not explicitly state face-down.