Hiden

or simply "secret" techniques are passed down orally from generation to generation in certain regions or clans.

The groups who possess these techniques are usually extremely secretive about them in order to ensure that no one other than the members of the group or clan learn them. As such, they are passed down through oral means instead of being written down or recorded. A few hiden techniques require a special ability or lineage and as such are usually the pride and fame of the clan that possesses them. Many hiden techniques are rooted in Yin–Yang Release, for example is Yin Release used in the Nara clan's Shadow Imitation Technique and Yang Release in the Akimichi clan's Multi-Size Technique. These techniques also cannot be copied through any means of simple observation.

They are not to be confused with kekkei genkai, as technically, hiden techniques can be taught to anyone.

Trivia

 * In Boruto: Naruto the Movie, Momoshiki Ōtsutsuki demonstrated the ability to absorb hiden techniques and regurgitate them.