Isshiki's Dōjutsu

This is the unnamed dōjutsu used that's earliest known wielder was Shibai Ōtsutsuki. The iris and pupil of this eye are yellow with a black wheel-like pattern with eight spokes coming out of the centre.

In the manga, after being killed and appearing before Code as a spirit, the number of spokes in his eye decreased to two. When Kawaki uses the dōjutsu, the number of spokes in his eye changes from one when he's not using anything, and two to four when using any technique.

Abilities
This dōjutsu allows the user to use Sukunahikona, the ability to shrink themselves and any inanimate object or nonliving matter within their sight. Accompanied with the technique is Daikokuten, which enables the user to store anything shrunk by Sukunahikona into a dimension where time does not flow at any moment. The dōjutsu can also summon large black cubes which can disrupt the techniques of a sensory type individual, as well as enabling the user to estimate their lifespan (chakra in the anime ) through a flame-like shadow.

Trivia

 * The dōjutsu's shape resembles the wheel of dharma, connecting it with the recurrent Buddhism motif associated to the Ōtsutsuki Clan.
 * Through Jigen, Isshiki could perform Sukunahikona and Daikokuten despite his host not possessing the dōjutsu, though the usage of the former technique is limited through hand signs.
 * For some reason, Jigen does not manifest the dōjutsu despite bearing Isshiki's Kāma; contrarily, Kawaki possesses the dōjutsu once his reimplanted Kāma activates.