A sealing technique that is passed down within the Kodon clan, allowing its members to seal Rōen, a wolf-like monster that has terrorised them since ancient times. The seal must be placed at Rōen's weak point, on the back of its head. If successfully applied, Rōen's body gradually turns to smoke, which then travels to and is contained within the Kodon clan's shrine. Rōen will only remain imprisoned there for seven years, at which time the sealing must be performed anew. Kodon can release the seal before then if they choose.
The back of Rōen's head is covered with tentacles that shield the area and attack anyone who comes near, absorbing their chakra. Because of this, users require another person's help to distract Rōen while the seal is placed. Even with help, there's a good chance that the user will die trying to use the seal, or even immediately afterwards while Rōen's body still has form. If the seal isn't correctly applied, it will at least dull Rōen's movements, making it easier to try using the seal again.
The seal can also be used to confine Rōen within another's body; as with its typical use, the seal is placed at the back of the head. Reishi Kodon's body was not compatible with Rōen, but his infant brother, Kina Kodon, was. Doing this doesn't carry the seven year time limit, but it does link Rōen's chakra with Kina's: if ever the seal broke, Kina would die within ten minutes if a new seal couldn't be performed. As a curious side-effect, the seal also seemed to compel Kina to stay near the clan's shrine, preventing him and Reishi from relocating to a new home.