Fūin jutsu (封印術, "Sealing techniques"), in the fictional anime and manga series Naruto, are jutsu that 'seal' a being inside objects or inside other living beings. The only thing that can't be sealed are wormholes and vortexes.
A jutsu performed by the Akatsuki leader, requiring several Akatsuki members and three days to complete. It is used to forcibly drain the spirit and chakra of the Bijū from their hosts. It is said that extracting the Bijū from the host Jinchūriki will kill the host, and from what we see of Gaara, it most certainly does.
This seal allows the user to seal nearby fire. The user writes the seal on a scroll and then performs the required handseals. This causes a vapor to appear from the scroll, enveloping the fire and sealing it on the scroll as the kanji for seal (封).
This seal is used in conjunction with the Shikokumujin. After the individual is sealed in the container, this seal is further added as a binding layer of protection. To create the seal, the user will write the incantation in blood on the sealing tag, attaching it to the container.
Gofu Kekkai (Five Seal Barrier)
Name: Gofū Kekkai, 五封結界, literally "Five Seal Barrier"
This jutsu is used to strengthen the seal on the Kyūbi. The original seal allowed Kyūbi's chakra to seep out into Uzumaki Naruto, but the additional seal disturbs this, preventing Naruto from using Kyūbi's chakra and even controlling his own chakra properly.
Gogyo Kaiin (Five Elements Unseal)
Name: Gogyō Kaiin, 五行解印, literally "Five Elements Unseal"
The Hakke no Fūin Shiki was used in conjunction with the Shiki Fūin to seal the Kyūbi within Uzumaki Naruto. The Hakke no Fūin Shiki allows the two Shishō Fūin to leak the Kyūbi chakra back into Naruto's own chakra.
A special written seal, created by Jiraiya, that when applied to Uzumaki Naruto's body will dispel all effects, including chakra, of the Kyūbi. This seal is probably S-ranked, because of its ability to seal the Kyūbi's chakra when it's already released.
During the timeskip, Jiraiya was witness to an event that triggered the Kyūbi's manifestation in a four-tailed state, causing great damage to Naruto's body (only to be healed by the Kyūbi) and completely subverting his human personality.
First used by the Yondaime to seal the Kyūbi inside an infant Uzumaki Naruto. The Sandaime Hokage also attempted to use this technique against Orochimaru. This Jutsu, when performed, ends the lives of both the target and the user. Using this technique invokes the powers of the Death God (Shinigami), which hovers behind the user. The Sandaime was badly wounded and near death when he perfomed this jutsu, and decided to seal Orochimaru's soul's arms instead of his whole soul (due to a lack of strength), making Orochimaru's arms unusable. It has been hinted that with the death of Sandaime, this technique is lost forever, though this is not confirmed.
This seal is used to reduce the effects of the seishingan drug. While under influence of this seal the drugged person won't die, but rather be put in a temporary coma. This forces the body of the person to be able to handle a level 2 cursed seal.
