Tengu format ruling
Thunder King Rai-Oh
Card effect (current official text)Neither player can add cards from their Deck to their hand except by drawing them. During either player's turn, when your opponent would Special Summon exactly 1 monster: You can send this face-up card to the Graveyard; negate the Special Summon, and if you do, destroy it.
Rulings
- The ② effect can only negate the Summon of a monster while there is no ongoing chain. (It can negate a Synchro Summon, or the Special Summon of Cyber Dragon by its own procedure. It cannot negate the Summon of a monster being Summoned by a card effect, such as by "Call of the Haunted"). It cannot negate the Summon of a monster being Summoned by a lingering effect, like "Future Fusion").
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.