Uchiha Secret Technique: Kotodama

It is a powerful fūinjutsu created during the that activates during the deathbed of an Uchiha, to prevent any attempt to get their Sharingan.

Overview
To protect that their dōjutsu fall into the hands of other shinobi who did not belong to the Uchiha clan, this fūinjutsu was created to prevent the Sharingan to be obtained by an enemy if its bearer died on the battlefield. For the seal be activated, the bearer of the Sharingan should do a blood sacrifice (as well as the Summoning Technique) and with their own blood must write the kanji seal in the palm of their hand, then still with their blood, the bearer must flick their eyelids with the middle finger and index finger dirty with blood. Thus, the seal is active preventing the Sharingan fall into wrong hands.

If the Uchiha bearer of the Sharingan is killed, in its deathbed the seal will be released by drawing on its face rectangular seals around the neck, cheeks and nose of the bearer furthermore a semicircle is formed on its chin and a circle is formed at the tip of its nose. In addition two tomoe (巴) are formed near the eyes of the user. When the seal is released and the technique is active, the eyes of the bearer are destroyed, usually being burned or become blind.

After is likely that this technique has been extinct since there is no knowledge that Sasuke or Obito Uchiha (excluding Madara for having been resurrected and Kakashi for not having Uchiha blood) know that seal or had already used it.

Influence
Kotodama or kototama (言霊, lit. "word spirit/soul") refers to the Japanese belief that mystical powers dwell in words and names. English translations include "soul of language", "spirit of language", "power of language", "power word", "magic word", and "sacred sound". The notion of kotodama presupposes that sounds can magically affect objects, and that ritual word usages can influence our environment, body, mind, and soul.

This Japanese compound kotodama combines koto 言 "word; speech" and tama 霊 "spirit; soul" (or 魂 "soul; spirit; ghost") voiced as dama in rendaku. In contrast, the unvoiced kototama pronunciation especially refers to kototamagaku (言霊学?, "study of kotodama"), which was popularized by Onisaburo Deguchi in the Oomoto religion. This field takes the Japanese gojūon phonology as the mystical basis of words and meanings, in rough analogy to Hebrew Kabbalah.

The etymology of kotodama is uncertain, but one explanation correlating words and events links two Japanese words pronounced koto: this 言 "word; words; speech" and 事 "situation; circumstances; state of affairs; occurrence; event; incident". These two kanji were used interchangeably in the name Kotoshironushi 事代主 or 言代主, an oracular kami mentioned in the Kojiki and Nihon shoki. Kotodama is related with Japanese words such as kotoage 言挙 "words raised up; invoke the magical power of words", kotomuke 言向 "directed words; cause submission though the power of words", and jumon 呪文 "magic spell; magic words; incantation".