This technique creates a barrier around a place by placing four "Forbidden" (禁, kin) tags around a fifth. The only way to remove the barrier is by removing all five tags simultaneously.
Not only would this require a group of at least five people, it also requires an immense search, since the four tags can be scattered in any direction, as far as 800 meters from the fifth seal. This makes breaking through this barrier almost impossible.
Even if the barrier is broken, there is a final obstacle. The Mirrored Sudden Attacker Technique will create perfect copies of those who have removed the seal, preventing them from returning immediately.
- Third Databook, page 255