Ningatō (jap. 忍牙刀, ninja fang sword) is Kurohabaki Clan's special attack.
The user runs towards an opponent and moves his head sideways. The user then pulls his head back and strikes with great force. The deepness of the cuts are depending on the intensity and force, and the attack may even tear off limbs. Masamune was able to cut off the head from the opponent with the technique, and used it to execute disobedient subordinates.
But revealed in GDReq, when done by Yamabiko in the fight against Ezoma, the attack has one weakness depending on how thick the opponent's skin is and force as well as intensity the user puts into the attack the user can break their entire lower jaw clean off.
Terumune knew how to perform the attack, and taught it to his sons Yamabiko and Masamune. Later, he also taught Rigel the attack too. Kenshin learned the technique by observing the movements of Masamune. At least Kurokirimaru of Kurohabaki also knew how to use the attack.
Characters capable of this attack: