Naka Shrine

The is a shrine in Konoha. In the main hall, beneath the seventh tatami mat from the far right, is a secret meeting place of the Uchiha clan. In there is a tablet containing the clan's secrets. The tablet can only be read with specific dōjutsu: the basic Sharingan is able to decipher a minimal amount of the information, even more of it if the person possesses the Mangekyō Sharingan, and only the Rinnegan is able to read the entire tablet. Here the secrets of the Mangekyō Sharingan are written, as is the story of the Sage of the Six Paths and the Ten-Tails.

Trivia

 * This location appeared in Naruto: The Broken Bond which also provided an achievement for Xbox 360 and called "Path of Darkness", The Naka shrine was regarded in the game as Sasuke's Hide Away or Sasuke’s Secret Room, it is however unknown if at the time the producers of the game knew what this shrine was since it was only shown to be a location that Sasuke was seen while grieving because of the Uchiha clan massacre and the thoughts of revenge against Itachi Uchiha. This site can be found in the Leaf Village in game but it's underneath the island in the south-west area of the village instead of under the main hall in the manga.
 * When Sasuke first approached the tablet to read it under Itachi's instructions, he somehow managed to read enough to understand the Sharingan's ability to control the Nine-Tailed Demon Fox, despite him not remembering that he awakened his Sharingan (and therefore, it was not active at the time of reading), and shouldn't have been able to decipher the text.