Eight Trigrams Sealing Style

The Eight Trigrams Sealing Style, consisting of two Four Symbols Seals, was used by Minato Namikaze to help Naruto Uzumaki access the chakra of the Nine-Tailed Demon Fox sealed within him. To perform the technique, the user must first summon a ceremonial throne, and place the target on it.

He claimed it was designed to hold an imprint of this seal's user (as well as the chakra and personalities of other people that the sealer chooses) as a failsafe. These imprints (as in the case of Minato and Kushina Uzumaki) have the capacity to recede the Nine-Tails' activity and interact with Naruto, talking to him for a limited amount of time. As time passes the seal weakens. As such, to strengthen the seal again when it gets too weak, Minato drew a key on the abdomen of the scroll toad Gerotora. The key can also be used to completely remove the seal.

When Orochimaru used the Five Elements Seal on Naruto, this created an imbalance due to an odd-numbered seal being placed over an even-numbered one. As a result, Naruto not only lost access to the Nine-Tails' chakra, but also had difficulty controlling his own, until Jiraiya removed it. Apparently, the seal is not automatically visible on Naruto's belly, but becomes perceptible when the latter draws power from the Nine-Tailed Demon Fox, a trait noticed by Orochimaru during their fight in the Forest of Death.