Forbidden Individual Curse Tag

This is a cursed seal that is placed directly on the target's heart.

Usage
The cursed seal is designed to restrict the target, in which it prevents them from taking their own lives and removing the cursed seal themselves. Directly striking the heart appears able to remove the seal, albeit risking one's life in the process. According to Obito Uchiha, the cursed seal also interfered with him becoming the Ten-Tails' jinchūriki.

Trivia

 * Both Rin Nohara and Obito Uchiha, who were branded with this cursed seal, had it removed by Kakashi Hatake's Lightning Cutter separately, although Rin died while Obito survived – albeit barely – because he sealed the Ten-Tails into himself shortly after.
 * In the manga, the tag is black, with a Rinnegan-like symbol on it, while in the anime, it is white, with a red, white, and teal symbol.