To say that a card is '''Faceface-down''' ('''Set'''), is to say that the back part of the card is facing up, and the face of the card is facing down. This is the opposite position of the card being [[face-up]].

Face-down [[Monster Card]] s can only be in horizontal position ([[Defense Position]]) unless with the effect of "[[Darkness Approaches]]", you can have it in vertical position ([[Attack Position]]).

When any card is face-down, unless specifically mentioned by a card effect, its controller is not permitted to disclose any [[Card layout#Description details|details]] of that card to his/her their opponent, even if that card was [[face-up]] on the [[field]] a short time ago. Shuffling face-down cards can disrupt gameplay and is not permitted, unless the effect of a card, like "[[Shifting Shadows]]" allows it.