Reishukaku

The, also referred to as the , is a device created and used by the Shiba Clan.

Overview
The Reishūkaku is a medium-sized orb composed of a clear material that is inscribed with a red crane insignia.

When infused with Reiryoku, the Reishūkaku produces a semi-transparent blue barrier, referred to as a, around the one holding it at the time that protects them from outside forces; with Reiryoku from multiple individuals pooling in it at once, the Reishūkaku can form a barrier strong enough to withstand the Shakonmaku, which normally disintegrates any spiritual bodies it comes into contact with. The shape, size, and consistency of the barrier varies between users. The Reishūkaku can also be used in direct combat for protecting the use from enemy attacks, as well as to save oneself from a fall by remaining suspended in midair and floating upward.

However, though its application is simple and straightforward, the Reishūkaku is not without risks when in use. Due to its need for a constant influx of Reiryoku to maintain its barrier, users can find themselves heavily fatigued after only a short period of activation, with even Ichigo Kurosaki, who possesses immense reserves of Reiryoku, ending up sweating and out of breath after multiple failed attempts to use it. Additionally, as Kūkaku Shiba warns, losing one's concentration while using the Reishūkaku can result in the barrier exploding, as demonstrated when Ichigo became briefly distracted after his successful creation of a barrier; this can also occur when the barrier is "melted" by an outside force like the Shakonmaku that can unravel its structure, resulting in a vortex of energy followed by an explosion powerful enough to separate its inhabitants and send them flying for several miles, as well as when it is pierced by a weapon, though this has the beneficial side-effect of trapping the enemy combatant holding that weapon and engulfing them in an explosion. Those with high levels of Reiryoku and little control in channeling it can inadvertently create a massive and dense barrier that damages its surroundings. Most notably, the Reishūkaku cannot be used by someone who does not know how to properly channel their Reiryoku, and when multiple people are channeling their Reiryoku into it, they must be careful to match their levels of output with each other in order to avoid destabilizing the barrier, which they can do by sensing the Reiryoku flow of each individual through touching the Reishūkaku itself; consequently, when he formed a barrier with his allies, Ichigo found himself unable to lower his Reiryoku output all the way down to their level.

Usage
During their rescue of Rukia Kuchiki, Ichigo Kurosaki and his friends used the Reishūkaku to break into the Seireitei with the help of Kūkaku Shiba, who fired them out of her Kakaku Taihō while they maintained a collective barrier and, with the help of her brother Ganju Shiba, directed the cannonball to crash into the Shakonmaku with Kagizaki; though it protected the Ryoka from the disintegrating power of the Shakonmaku, the already-unstable barrier was melted by the impact and briefly turned into a vortex of energy, sending Ichigo and his friends flying in different directions across the Seireitei. The fate of the Reishūkaku after this remains unknown.