Dark Sealing Method

In order to help an individual advance their cursed seal to its second level, the Sound Four use the Four Black Fogs Formation. After the individual and the Black Fogs have been placed within a confined space, such as a coffin, Sakon uses the Dark Sealing Method: he places five talismans, each inscribed with sealing formulas written in his blood, around the coffin's rim. This creates a barrier around the coffin, keeping the Black Fogs contained until the cursed seal's advancement has completed. So long as the barrier is in place, even the Byakugan is unable to see within it.