Advanced format ruling
Blackwing - Kalut the Moon Shadow
Card effect (current official text)During either player's Damage Step, when a "Blackwing" monster you control is attacking or being attacked: You can send this card from your hand to the Graveyard; that monster gains 1400 ATK until the end of this turn.
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.