Advanced format ruling
Tsukuyomi
Card effect (current official text)Cannot be Special Summoned. If this card is Normal Summoned or flipped face-up: Target 1 face-up monster on the field; change that target to face-down Defense Position. Once per turn, during the End Phase, if this card was Normal Summoned or flipped face-up this turn: Return it to the hand.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.