Historical Rules · 8 March 2024
Rule 702.49c
Official source text from the 8 March 2024 Rules release
A ninjutsu ability may be activated only while a creature on the battlefield is unblocked (see rule 509.1h). The creature with ninjutsu is put onto the battlefield unblocked. It will be attacking the same player, planeswalker, or battle as the creature that was returned to its owner’s hand.