Sekīatsu

Sekīatsu (跡威圧, "Scar of the Forces") is an advanced Zanjutsu that combines the principles of Kendō and Iaidō.

Overview
In a battle between spiritual beings, such as the Shinigami, it is a struggle between spiritual pressure in which the stronger force subdues the weaker force. Despite this, the weaker force continues to struggle for control in this war of energy and wills. At the exchange of these pressures, there is a point in which potential spirit energy is built up because of this ongoing fight. By being capable of cutting through this "scar" of sorts that forms between the user and the opponent's spiritual pressures with a Kendō swing that carries a resolute will without any form of wavering whatsoever, one may release the trapped energy and fire it as an enormous wave of spiritual power. It is likened to the Getsuga Tenshō in its appearance.

Usually the wave of energy is composed of the colors of both opposing spiritual energy, but in the hands of a master, it is energy that succumbs to the will of the swordsman and reflects this; in his case, the energy wave takes on a white color. It is considered a dangerous attack because its effectiveness and overall attack strength is derived from the level of both the user and the opponent, varying in proportion as well as in its shape and size. The Sekīatsu can be deemed a one-hit kill technique if executed properly and strikes the target head-on, due to the fact that it is just as powerful as the reiatsu being emitted from the target themselves, meaning that regardless of the defenses or the strength they may possess, it is as if they were being struck by their own great power.

The user, upon cutting through this scar, can shape the released energy in any manner he may wish. Additionally, if he is facing an opponent whose reiatsu is reflective of their Zanpakutō's elemental power, such as fighting an opponent with a fire-type weapon, the Sekīatsu itself will take on fire properties, including the power to burn through its target. This applies to other Kidō-type Zanpakutō as well. The Sekīatsu is a technique that requires not only an extremely high competence in Zanjutsu due to needed a finely-tuned bladed strike to actually manage to cut through the scar between spiritual pressures but also a very strong will to execute properly, otherwise the energy released from the point of potential may explode in all directions, damaging both the user and the opponent severely.