Chapter Level reference to understand Gojo stats
Zankensoki(Cut-Fist-Run-Spirit): Basic Shinigami fighting techniques.Zanrefers to sword fighting techniques.Kenrefers to unarmed fighting techniques.Sorefers to moving techniques.Kirefers to Kido
ZANJUTSU : Sword fighting techniques for the Zanpakuto. The most basic fighting technique. The ranks from high to low are MASTER(ex: Soi Fon) , EXPERTS(Ex: Yoruichi) , SWORDMEN(Ex: Hanataro yamada )
HAKUDA : An unarmed fighting technique that makes use of one's own body in a fight. The ranks are MASTER(Ex: Yoruichi) , EXPERT(Ex: Isshin Kurosaki(shiba)) , COMBATANT(Ex:Byakuya Kuchiki), PRACTITIONER(Ex: Rangiku Matsumoto)
HOHO : The name for all high-speed fighting movements based on the art of Shunpo. Ranks are MASTER(Ex: Yoruichi) , EXPERT(Ex: Renji Abarai) , PRACTITIONER(Ex: Rangiku Matsumoto) ,
KIDO : Advanced spells that require strong spiritual power: Hado(way of destruction) and Bakudo(Way of Binding) and Kaido( Healing spiritual art). There are also Forbidden Kido The use of such spells will commonly result in some form of lengthy imprisonment or worse. The Kidō spells which fall under this class are those which involve the manipulation of space and time and Kidō which sacrifices the self.
The rank are MASTER(Ex: Sosuke Aizen) , EXPERT(Ex: Rukia Kuchiki) PRACTITIONER(Ex: Renji Abarai)
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REIRYOKU LEVELS:
Basic Spiritual Power: This level of spiritual power corresponds to those possessing a level of spiritual power that is minimal. This level of power is common among those who may or may not be spiritually aware to a small degree but otherwise have no real spiritual power. This is also a common level of power for a regular human.
Average Spiritual Power This level of spiritual power corresponds to those possessing an average level of spiritual power. This level of power is common among those of significant spiritual awareness and may even possess powers of their own but the power levels can vary among individuals. This is also a common level of power for a low ranking seated and non seated members of the Gotei 13 or lesser power individuals.
High Spiritual Power : This level of spiritual power corresponds to those possessing an above average amount of spiritual power, which is finely controlled. This level of spiritual power is common among those of an average lieutenant rank and high ranked seated officers. (Lieutenant-class)
Great Spiritual Power: This level of spiritual power corresponds to those possessing a large amount of spiritual power which is finely controlled. This level of spiritual power is common amongst those of an average Captain rank. (Captain-class)
Immense Spiritual Power This level of spiritual power corresponds to those possessing an enormous amount of spiritual power which is finely controlled. This level of spiritual power is reflected in its ability to enhance a user during combat as well as its ability to affect the surrounding environment on a controlled level, allowing the wielder to use it in combat to startling degrees. (Advanced Captain-Class)
Immeasurable Spiritual Power This level of spiritual power corresponds to those possessing a colossal amount of spiritual power, which can be controlled to varying degrees depending on the individual. This level of spiritual power is very rare and reserved for the strongest beings. (Beyond Captain-Class)
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DIFFERENCE BETWEEN REIRYOKU AND REIATSU
Firstly let me make something clear. A common mistake most readers make. REIATSU isn't the energy level.
The difference between spiritual energy and spiritual pressure is simple: Reiryoku(spiritual energy) is the amount of energy a being has stored within their body or soul, whereas Reiatsu(spiritual pressure) is the pressure that a person's Reiryoku exerts. In other words, Reiryoku is potential while Reiatsu is energy in use and can be sensed by other spiritually aware beings. In general, those with high levels of Reiryoku will often have the highest levels of Reiatsu also. A skilled warrior can overcome a person possessing greater Reiryoku by possessing greater Reiatsu - this is achieved by having greater control over their own spiritual energy.
Also the amount if Innate Reiryoku is important but it can be increased with training. All shinigami go through this process. Aside from some cheated bastard like Ichigo who had insane amounts of energy from the beginning and were only unable to properly use it. The bastard was already at Immense level from the start and later reached immeasurable.