Historical Rules · 5 October 2018
Rule 711.1b
Official source text from the 5 October 2018 Rules release
A double-faced card’s back face is marked by a back-face symbol in its upper left corner. On Magic Origins and Core Set 2019 double-faced cards, the back-face symbol is a full Planeswalker icon. On cards in the Innistrad block and Shadows over Innistrad set, as well as on Ulrich, Uncontested Alpha in the Eldritch Moon set, the back-face symbol is a crescent moon. On other Eldritch Moon double-faced cards, the back-face symbol is a stylized image of Emrakul. On Ixalan cards, the back-face symbol is a land icon.