Rinne Sharingan

The is a dōjutsu kekkei mōra and the predecessor to the Rinnegan and Sharingan. It is characterised by red sclerae and irides, with a ripple pattern spreading over the eyeball and nine tomoe.

Background
This dōjutsu was first manifested by Kaguya Ōtsutsuki as a third eye on her forehead after eating the chakra fruit of the God Tree. It was also possessed by the Ten-Tails, the result of Kaguya merging with the God Tree. According to the stone tablet handed down in the Uchiha clan, when one who wields the power of Rinne approaches the moon, the eye which can reflect off the moon and grant the infinite dream will open. This was proven true when Madara Uchiha, as the Ten Tails' jinchūriki, was able to manifest this dōjutsu in his own forehead after regaining both of his Rinnegan. As a result of Black Zetsu's actions, Madara's body then served as a vessel for the resurrected Kaguya, who retained the Rinne Sharingan. When Naruto Uzumaki and Sasuke Uchiha later used the Six Paths — Chibaku Tensei to seal Kaguya, her third eye was closed by a horizontal eyelid with the appearance of a sun and moon under the effects of the technique.

Abilities
The Rinne Sharingan possesses the ocular power of the Sharingan, and can be used to cast the Infinite Tsukuyomi, an extremely powerful genjutsu which can only be countered by the Rinnegan and the chakra of the nine tailed beasts. Using this dōjutsu, Kaguya can transport herself and those in her vicinity to a series of alternate dimensions.

Trivia

 * The kanji is also used in Sharingan and Rinnegan, potentially linking the three terms etymologically.
 * When the Ten-Tails was revived by Obito, its eye was consistently depicted with only six tomoe. This may be a result of the beast being revived in an incomplete form due to the Demonic Statue of the Outer Path having absorbed only fragments of Gyūki and Kurama's chakra. When the beast transformed into a construct of the God Tree, its eye was shown to possess nine tomoe once more.
 * Sasuke referred to the Infinite Tsukuyomi as a genjutsu cast by the Rinnegan.
 * Despite not possessing the Rinne Sharingan himself, Obito Uchiha attempted to cast the Infinite Tsukuyomi by manifesting a construct of the God Tree outside of his body as the Ten-Tails' jinchūriki.
 * There have been a number of times the dōjutsu has been depicted incorrectly:
 * During the Ten-Tails' battle with Hagoromo and Hamura Ōtsutsuki, its eye was depicted with at least four rows of tomoe.
 * After casting the Infinite Tsukuyomi, Madara's Rinne Sharingan was depicted with only six tomoe.
 * On various occasions, Kaguya's Rinne Sharingan was depicted with six or three tomoe.
 * The eye in the crystal ball used to cast the Limited Tsukuyomi contained seven tomoe, possibly reflecting the number of tailed beasts captured by Akatsuki.
 * In Naruto Shippūden: Ultimate Ninja Storm 4, Sasuke's Rinnegan is erroneously referred to as a Rinne Sharingan, while initially in the digitally coloured manga, his Rinnegan is red, resembling the Ten-Tails' six tomoe Rinne Sharingan.