Read: IMPORTANT! (Zanpakutō)

Zanpakutō are the trademark weapons of the Shinigami. Capable of cutting spiritual bodies, they are amongst the few weapons which can be used to combat Hollows. Each Shinigami carries a Zanpakutō, and each Zanpakutō is unique: as the swords are both reflections of a Shinigami's soul and power, and sentient beings unto themselves. The Zanpakutō's name is also the name of the living spirit that empowers the sword and lends its strength to the Shinigami who wields it. These beings can vary greatly in appearance and have their own distinct personalities which match their owner's. Normally, the Zanpakutō spirit can only be seen by its wielder. Otherwise, they dwell in their own "inner world", created within the minds of the Shinigami who wield them. As such, each Shinigami's inner world is drastically different from another Shinigami's and is unique to themselves. A Zanpakutō's spirit can bring its wielder into its inner world, though Shinigami can voluntarily achieve this simply by meditation.

A Zanpakutō's shape and abilities are based on their Shinigami's soul. Once a Shinigami learns his/her sword's name, they are able to communicate with one another and grow stronger together. Zanpakutō are born with their Shinigami and they die along with their Shinigami. Shinigami use them in battle as a reflection of their heart. When released, they can display a vibrant power. They are one with the Shinigami, and they share a Shinigami's conviction.

Asauchi - The class of nameless Zanpakutō that all low-class Shinigami wield. Shinigami who are still in training - those who do not yet belong to any of the Gotei 13 - all wield generic Zanpakutō. Shinigami who are unable to communicate with their Zanpakutō, the "shallow hit", which refers to the grossly reduced power of a Zanpakutō whose wielder cannot connect with it properly.


Facts:
■Because they are part of their owner's soul, a Zanpakutō cannot be replaced, though it will slowly regenerate if it is broken.
■The Zanpakutō size reflects the amount of the swordsman's spiritual power.
■If a Shinigami pierces the chest of a human with their Zanpakutō and channels their Reiryoku through it into the Human's body, it will transform that human into a Shinigami temporarily. The act does not have a high chance of viability even when the human in question has a high level of spiritual energy, and if the method does fail the human will die.
■Every Zanpakutō has its own name.
■A Zanpakutō can determine whether or not its wielder is worthy of its power.
■Normally, even a broken Zanpakutō would return to its original state as its wielder recovered.
■Zanpakutō have a true form.This true form resides inside their Shinigami. A Zanpakutō has a mind, and a body that controls their powers. Shinigami are able to grow more powerful by communicating with them.
■Zanpakutō possess their own reiatsu, which can be sensed as any reiatsu can and is identical to that of their wielder though with subtle differences.
■Though rare, it is not impossible for more than one soul to be attuned to the same spirit. In such cases, ancient law of the Soul Society will not allow two beings to wield the same Zanpakutō, in which case, they must duel for ownership of the spirit, with the winner gaining it and the loser being sentenced to death.
■No matter what form (or size) a Zanpakutō takes, it is always virtually effortless for its owner to wield because it is a part of its owner's soulShinigami captains all consciously keep their Zanpakutō in a manageable size, otherwise they would be holding Zanpakutō the size of skyscrapers. Therefore, one cannot judge one's opponent's strength solely by the size of their Zanpakutō.


A wielder knows their Zanpakutō spirit very closely and vice versa. The connection is very deep, though in the beginning the connection is one sided with the wielder being unable to fully hear the spirit communicating with them. It is not uncommon for the introduction of the two (Shinigami and Zanpakutō spirit) to take place in the inner world while the prospective Shinigami sleeps.

A Zanpakutō is generated by its wielder upon the solidification of their Reiryoku into the sword's form. Commonly, when a Shinigami graduates from the training academy, he/she gains his/her own unique weapon. The process by which this happens has not yet been shown. What has been shown is that Ichigo Kurosaki, who was trained independently and in an unusual manner, gained his own Zanpakutō via a test of combat that required him to reach deep within and take hold of his own power in a way he never had before. Whether this is the same process other Shinigami go through is not yet known. At any rate, it is known that when a Shinigami obtains their own Zanpakutō, they learn its name and become able to "activate" it. This activated ability is called the "Shikai," the first of two levels of activation. When a Zanpakutō sword is changed into its Shikai form, what is actually being seen is the true form of the weapon.

Wielding a Zanpakutō is more than a simple matter of skill in swordsmanship. Since the swords themselves are alive, a Shinigami must obtain his or her sword's co-operation to truly maximize its performance. This can be done in a variety of ways, though it seems that the orthodox approach involves subjugating the sword; the Shinigami belonging to the Thirteen Divisions keep their swords sealed into the forms of ordinary katana and have strict rules about when and where they are allowed to release their true forms. Keeping a sword in its unsealed form all the time seems to be considered gauche, as a sign of carelessness and/or inexperience. The Shinigami also use certain phrases when they activate their swords, which appear to be necessary to release the seals keeping the swords' powers bound. These are always phrased as commands, further emphasizing the "subjugation" aspect of Zanpakutō control. Most swords have at least one, though some Shinigami use more than one to command their weapons.

It is not enough to simply know the name of one's Zanpakutō. If a wielder were to lend its power to its Zanpakutō then the weapon would become stronger. To fully use a Zanpakutō's power, a wielder must get to know its Zanpakutō's spirit.

Jinzen (Blade Zen): This method is the only way to carry on a proper conversation with one's Zanpakutō. One places their sword over their lap and takes a meditative pose and then forces their mind to become one with the Zanpakutō.

In this form, one can call out the true form of the powers of their Zanpakutō. This form is something that Soul Society has worked out over the thousands of years since its formation. It is entirely about speaking with one's sword. This advanced form of training is far different from attaining abilities by force. In this form it is about entering a state of calm to enter the inner world of the Zanpakutō and engage them there. In this state a wielder will have to fight their Zanpakutō spirit in order to attain access to new abilities, the Zanpakutō spirit does not want to teach these moves and engage the wielder in a battle the likes of which has never taken place before.

In this meditative state, one is so deeply entranced that even sustained wounds are ignored. Any form of injury sustained in the inner world while in this meditative state is reflective in the real world.


Mood & Communication-

As stated, a Zanpakutō is a being unto itself and tends to be highly temperamental. Its mood is determined by how it is treated by its Shinigami as well as its overall personality. This allows a Shinigami to partially determine whether it will achieve its true power or not. For example, Yumichika Ayasegawa normally releases his Zanpakutō with the name Fuji Kujaku (Wisteria Peacock), even though its true name is Ruri'iro Kujaku (Azure Peacock), knowing that its favorite color is azure and that its least favorite is wisteria purple. He does this so that its true power is not seen. Since his Zanpakutō hates the nickname, it becomes moody and only releases a fraction of its power. This allows him to pass off his Zanpakutō as a simple melee-type rather than what it truly is, a Kidō-type, something that is unacceptable in the 11th Division due to an unspoken rule that all Zanpakutō in the 11th Division must be melee-types. Only when its true name is uttered does it achieve full potential.

Another major exception to just about all of the aforementioned rules, 11th Division Captain Kenpachi Zaraki, somehow failed to learn his sword's name. He ignored its living embodiment and preferred to use it simply as a tool, relying only on his own power. He never developed the control to seal his power, and thus also breaks the rule/tradition of keeping a Zanpakutō sword in a sealed form--his sword is always in its true form. Zaraki's immense personal strength not only made it possible for him to break these rules, but also to rise to the rank of captain. However, his neglect wasn't exactly good for the weapon, causing immense pain to its embodiment and damage to the sword itself.