Shisō Kekkai (Kenji)

Shisō Kekkai (四葬結界, Quad Burial Barrier) is a high-levelled Kidō spell designed to seal away dangerous individuals. Historically the spell has been used only twice: the first by and  to seal away, and secondly by Hachigen Ushōda to temporarily seal away Averian. Whilst undoubtedly a powerful seal all one needs to do to break the seal is utter an incantation whilst standing in the seal's presence.

History
Shisō Kekkai was designed specifically to seal away dangerous threats, but its use was rarely needed for the was usually sufficient to the task. 's rebellion marked the first time Shisō Kekkai was used beyond testing purposes. So long as a Shinigami's heart is beating their reiatsu cannot be stopped; for this reason anyone whose heart cannot be stopped by an executioner of the Gotei 13 is sentenced to the. Shisō Kekkai exists for those who manage to evade justice and cannot be killed through conventional means, which was the same conclusion reached by Tadashi Kori and Shin Nagakura when they sought a means to deal with Averian.

Description
Shisō Kekkai requires a great deal of preparation, not to mention a Kidō master just to perform, and is executed in two key steps. Four halberds are integral to the first step with each halberd being attached to the target's primary limbs, which produce bolts of lightning to restrict the target in a circle-shape. The second step involves the actual sealing and encloses the target in a coffin, which is then impaled by the halberds. The coffin itself is highly durable to attack, not to mention the passing of time. In fact the only thing that can release the seal is a specific incantation. When used by Yamamoto and Hachigen the two brought their hands together to guide the sealing. Hachigen also used his to further empower the seal.

Improvement
Tadashi Kori led the attempt to seal Averian just prior to the outbreak of the First Spiritual War, for he and Shin correctly deduced that they and the Visored could not kill him. By using his Bankai, Shukketsushi Shirenya, Tadashi bound and constricted Averian before Hachigen then used Shisō Kekkai, which strengthened the sealing.

Incantation

 * Execution Incantation: Unknown.
 * Release Incantation: Unknown.

Practitioners

 * Hachigen Ushōda.
 * Hachigen Ushōda.