Juinjutsu (呪印術, literally meaning: Cursed Seal Techniques) are a type of techniques used to bring someone under the control of the user. By applying a seal to the victim's body, the user brings the victim's abilities and actions under his/her control.
With a simple secret hand seal, the user can inflict great mental and physical torment on the victim. The exact workings of juinjutsu are kept secret.
- The markings around Shukaku's body are naturally a cursed seal, allowing it to seal its opponents.
- Naruto chapter 658, page 10