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This article is about the real life information about Project Alicization and its mechanics. For information about events within Underworld, please see Underworld. You may also be looking for the anime episode with the same name.
Seijirou explaining the concept of ALICE to Asuna and Rinko - S3E06.png

Project Alicization (プロジェクト・アリシゼーション, Purojekuto Arishizēshon?) is a top-secret government project run by Rath to create the first Highly Adaptive «Bottom-up Artificial Intelligence (Bottom-up AI)». The Japan Self-Defense Forces (JSDF) intended to use the AI for unmanned weapons to improve Japan's inferior defence technology compared to the West, and to replace soldiers in wars to minimize human casualties. The name Alicization is formed from the acronym A.L.I.C.E (Artificial Labile Intelligent Cybernated Existence, or a highly adaptive artificial intelligence)[1][2], in reference to the project's goal of turning artificial human Fluctlights into «Alice». The project was mainly conducted within Rath's main base, the «Ocean Turtle», though a secondary alternate facility in Roppongi was also used.


With the end of the Cold War Era and subsequent collapse of the Soviet Union, the people became less tolerant of soldier deaths. However, countries with large militaries, especially the United States of America, were unwilling to abandon their military-industrial complex, thus necessitating unmanned weapons to replace soldiers. However, due to Japan's market not being capable of sustaining domestic production of weapons from scratch as a result of export prohibitions, Japan was forced to either import or co-develop weapons with America. Despite this mutual cooperation, America claimed the cutting-edge technology for itself, while the weapons sold to Japan lacked key features, such as control software for fighter jets. Thus, feeling anxious about relying on Americans for their core defensive capabilities, some military officers and technicians decided to create a technology that would entirely belong to Japan.[1]

History and development[]

Early Experimentation[]

The creation of a true adaptive «bottom-up» type Artificial Intelligence requires replicating the structure of the human consciousness, a quantum field known as a «Fluctlight». For this purpose, the technicians at Rath developed the «Soul Translator» (STL), a 4th generation FullDive machine capable of reading and copying a human's «Fluctlight». Additionally, they also developed the Light Quantum Gate Crystal (Lightcube), a special quantum computer with the capacity of storing hundreds of millions of qubits worth of Fluctlight data, allowing it to serve as a medium for copied Fluctlights. However, attempts at cloning an aged human's Fluctlight proved to be futile, as the clones could not handle the fact that they were not the originals, thus resulting in their mental collapse after an average of three minutes.[1]

After a week of brainstorming, an alternative plan was created. The staff attempted to limit the memories of the cloned Fluctlights, as a Fluctlight without memories of any personal information, such as a name or address, was unlikely to experience an existential crisis about being a copy that would lead to its collapse. However, this plan also proved to be a failure, as learning is a form of memory, thus losing the memory of successfully executing an ability would lead to the loss of the ability.[1]

Subsequent Experimentation[]

Ultimately, it was decided to clone the Fluctlights of newborns, as they had not accumulated any memories yet. This plan was successfully implemented by scanning the Fluctlights of twelve newborns. According to Higa Takeru, Fluctlights — especially those of newborns — lack the kind of physical differences that genes have, meaning that a newborn Fluctlight clone would not have a specific personality. This allowed the creation of a «Soul Archetype», which could then be inserted into the virtual world where it could grow and develop into a new individual.[1]

Creation of Underworld[]

The world for nurturing the Artificial Fluctlights needed to be nearly equivalent to the level of modern society in order not to cause issues with their development. However, even the Soul Translator was incapable of completely recreating an entire world. As such, it was decided to bring the level of the civilization in the virtual world to a past era, to a time when science and philosophy were just discovered, making it easier to nurture the AIs under certain conditions and to prevent them from realizing that their world is fake. However, as the people behind the project were oblivious to the cultural and societal norms of the past era, they instead came to a consensus that the creation an original setting for the world with limited space and customs dictated by the staff would suffice for their goal. Any potential issues could then be resolved by explaining them as so-called magic.[1]

Although creating a virtual world within the Soul Translator mainframe would not require any 3D data, customising the world would be a tedious effort. Therefore, «The Seed», a free compact version of the Cardinal System, was downloaded and used to create the villages and landscape of the new virtual world. This data was then converted to mnemonic visuals with the STL, creating a dual-layered world that was constantly synced with a server that contained the data for the world itself. The Cardinal System was left in charge of balancing the newly created world that was dubbed «Underworld».[1]

Development of Underworld[]

The first sixteen AIs were created and nurtured in two farming families, with NPCs fulfilling the role of other villagers. However, the first generation AIs could not be raised by another AI, hence four Rath employees volunteered to enter Underworld and raise the AIs to the age of eighteen (with the Fluctlight Acceleration (FLA) rate set to 1000, equivalent to one week had passed in real life). Afterwards, the employees were logged out by simulating their death via an “epidemic” and their memories of brief stay in Underworld were suppressed. After the volunteers logged out, the FLA rate was increased to 5000 and the initial sixteen AIs — four boys and four girls in each of the two families — formed their own families with ten children afterwards.

As the children were raised and eventually formed families of their own, the number of Artificial Fluctlights in Underworld quickly multiplied and gradually replaced the NPC villagers. After 300 years of simulation (or three weeks of reality), the population of Underworld grew to 80,000 and the Artificial Fluctlights expanded from a small village to occupying most of Underworld, with central government being formed and subsequent founding of religion. Feudal system soon appeared with the royal families and the Axiom church at the apex of the Underworld hierarchy.

Although this system was uncalled for in the first place, it likely came about as one of the four Rath workers had other intentions while nurturing the first generation of AIs. These thoughts and feelings were then passed onto their offsprings, causing the feudal system to materialize.

Underworld Experiment Problems[]

However, even though the AIs were growing with the same level of intellect as humans, a problem was discovered. Namely, in the 300+ years of simulation there had not been a single war, not even a single killing, due to the Artificial Fluctlights being overly obedient and not being capable of breaking any laws or rules set upon them.

Early Testing[]

The first attempted experiment to test the obedience of the residents of Underworld was called the «Overload Experiment». This involved causing the crops and livestock in the farms of an isolated village to die off to such an extent that the villagers would not have enough food to last through the winter, unless they abandoned a certain group of villagers so that at least the others could survive, therefore disobeying the Taboo Index by killing someone. However, the experiment turned out be a complete failure, as the villagers distributed their meager harvest among all villagers and none of them survived the winter due to starvation. This experiment proved that the residents of Underworld are not capable of breaking the law even for their own survival.[1]

Due to the results of the previous experiment, it was necessary to find out why the residents of Underworld were not capable of disobeying the law. Thus, another experiment was proposed. Eight volunteers from Rath were chosen to have their memories blocked and they were to grow up in Underworld from birth to the age of ten again in all sorts of environments to see if their actions would be similar to those of the Artificial Fluctlights. The result was that not only did none of the eight test subjects break the Taboo Index before the age of ten, but they also turned out to be less lively and curious of their surroundings than the regular residents due to a sense of discomfort. This was because their memories could not be erased completely, making them unable to get used to the life in Underworld, since the world does still differ from the real world.[1]

Later Testing[]

Finally, it was decided that a new test subject, who is used to living in a VR world and would not feel discomforted while living in Underworld was required. Kirigaya Kazuto was selected for this role due to his experience with living in virtual worlds for extended amounts of time, namely the game «Sword Art Online». He was also chosen because of the level of proficiency he displayed and capability to adapt within the game. Unlike the testers from Rath, Kirito exhibited an unseen level of curiosity and activity, being on the verge of breaking the Taboo Index many times, although he never actually broke any of the laws. However, Kirito's influence did make Eugeo and Alice Zuberg, the people closest to him, more likely to break the Taboo Index, until one day, Alice finally broke one of the clauses of the Taboo Index by touching the soil of the Dark Territory in an attempt to save the life of a dying Fluctlight. However, due to the time in Underworld passing at a much higher rate than in the real world, by the time the staff at Rath managed to notice that somebody had broken the Index, two days had passed in Underworld and Alice had already been transported to the Central Cathedral of the Axiom Church, where she was forcefully synthesised.[1]

Load Test Stage[]

The «Final Tolerance Experiment» (負荷実験段階, Fuka Jikken Dankai?, alternatively, "Final Load Test") is the final phase of the project, during which, the residents of the Human Empire were intended to face off against the creatures of the Dark Territory. A gradually increasing «load parameter» gradually increases the amount of endemic diseases, rampancy of dangerous beasts, poor harvest of crops, eventually causing an invasion of the Human Empire by the Dark Territory. This parameter cannot be changed even by a being with maximum System Control Authority, thus the Dark Territory's invasion on the Human Empire is inevitable. This phase is meant to test what kind of resistance the residents of the Human Empire would exhibit as their world slowly crumbles.[3]

System mechanics[]


Unlike the usual VR games, there is no game menu in Alicization. Instead, a Status Window called a «Stacia Window» can be called out for any object and person by drawing a seal shaped like the alphabet letters S and C with one's hand and tapping the target that one wishes to inspect. However, as the «Stacia Window» is considered as a basic form of «Sacred Arts», calling out the window for larger objects is considerably more difficult than for smaller objects and requires sufficient practice and knowledge in the Sacred Arts. The Status Window shows the ID and current/maximum «Life» values of the targeted object, as well as the item's Priority class if the item is a weapon, or Object Control and System Control Authorities if the target is a sentient being.

As a menu does not exist, an item storage feature does not exist either, meaning that all items need to be carried by hand, while clothes and weapons can be equipped the same way as in real life, instead of via a menu. Logging out manually is also impossible due to this, and it is presumed that only an Administrator can log a player out from within the game, though Kirito speculates that dying in-game might also lead to logging out.


The stats for any object or living being can be viewed by calling out a «Stacia Window» for them. Everything in Underworld has a property called «Life» while humans also have stats called «Object Control» and «System Control» Authorities and certain items, like tools and weapons have a property called «Priority». The OC and SC authorities were implemented for the project's «Pressure Experiment Stage», during which, the residents of Underworld were meant to battle with creatures from the Dark Territory to strengthen themselves.

Unit ID[]

The Unit ID is a parameter that most every object and living creature has. This ID is typically alphanumeric, and is seemingly ordered by the sequence in which that object was created in a specific category. The Unit ID usually begins with a string of characters that identify the category they belong to. For example, «WLSS», which is presumed to stand for «Double-edged, Long Sword, Single-hand»,[4] usually precedes any unit that has the aforementioned characteristics.

Additionally, Human Units also have a Unit ID that can be seen when bringing up a Stacia Window. This Unit ID is preceded by a string of characters, which likely identifies the location in Underworld that the Unit was born in.[5] Integrity Knights also have a secondary ID, which identifies them as "Integrator Unit"s and consists of three numerical digits. This secondary ID is not proceeded by a string of characters, so it is presumed that this ID is somehow different from the usual Unit IDs.

These IDs, for both Objects and Living Units, can be utilized with Sacred Arts for various purposes, such as locating a Unit, or modifying one of a Unit's many parameters.


«Life» (天命, Tenmei?, "Durability" in a status window) is the name given to the durability or HP value of each object or living being in Underworld. Unlike in RPGs, a user's Life is not displayed in their interface and can instead be checked by calling out a Stacia Window. The maximum amount of Life each individual has increases with age, peaking for humans at around twenty years old, but starts decreasing after the peak of one's lifespan is reached. Each object and living being has a different amount of Life available, which seems to depend on the lifespan of their real life equivalents, for example, insects and flowers have far less Life than trees and rocks. Life measures the current state of each object and depends on the conditions the object is kept in.

Most objects in Underworld do not disappear immediately after running out of Life. Most of them start a new count of Life as shards, fragments or carcasses, though the Life of such broken objects decreases at a far greater rate and disappears completely, without a trace, once the Life reaches 0 again.

For food, Life gradually decreases with time, but the rate of Life decreasing greatly increases in hot weather and, once the Life of food runs out, it becomes rotten, causing various illnesses if such food is eaten.[6] For clothes, Life controls various defects and stains and will drop rapidly if the clothes are not washed.[7]

For humans, Life drops at a rapid rate if injuries and illnesses are not treated in a timely manner. Bleeding is especially dangerous to a person's Life, as it causes a constant decrease in Life, making Life recovery rituals useless until it is sealed. Bleeding can be stopped by either sealing the wound, for example with cloth or any similar material, or by using special Sacred Arts. Fatigue in the world is treated as an illness, thus a person's Life drops with extensive running, holding on to large weight or anything else that leads to fatigue. A user becomes weaker as their Life decreases, even resulting at the user becoming unconscious when their Life reaches a critical level. Although there is no other way to control one's maximum Life aside from Administrator-level rituals, the currently available Life can be restored via medication and Sacred Art rituals (the most effective being the risky Life transfer rituals), though they cannot increase it beyond the maximum limit.

When a human's Life reaches 0, white arrows of light rain down on the said person, causing the insides of their head to be shaved away bit by bit, in other words, the system begins deleting the person's Fluctlight. A dead human can still be revived, unless important parts of the Fluctlights are shaved off before the ritual takes place. A resurrection can never be done perfectly, as the bits of Fluctlight that are shaved off until the ritual is cast cannot be restored. In a best case scenario, the revived person will only have lost their memories of the past few days.[8]

Object Control Authority[]

«Object Control Authority», abbreviated as OC Authority, is a parameter that determines what kind of tools, weapons and armor the person can wield. A person needs to have an OC authority equal to or higher than the item's «Priority» class to be able to wield the item properly. Swords that have a higher Priority than a person's OC authority cannot be used to perform «Secret moves», i.e. Sword Skills and they will feel much heavier than they should to the user. A sword's Priority determines the maximum hit combo Sword Skills that can be used with it and higher Priority items are also capable of breaking lower Priority items. The OC authority parameter can be increased by killing any creature that is capable of moving, even other people, but a larger increase in the parameter is awarded for killing creatures from the Dark Territory.

System Control Authority[]

«System Control Authority», abbreviated as SC Authority, is a parameter that determines what «Sacred Arts» rituals one can use and their success rate. Like OC authority, SC authority can be increased by killing any creature capable of moving, creatures from the Dark Territory providing a bigger increase, or through steady use of the rituals, even if they are not performed successfully, but with a bigger increase with successful difficult ritual usage.

Hidden parameters[]

Aside from the visible parameters like Life, OC and SC authority, several hidden parameters for each being exist as well. One of such parameters is called «Transgression Quotient» (or «Taboo Breaking Index») that measures the person's compliance to the law and rules through their speech and conduct which is converted in numerals. This parameter was originally meant to be used by Rath employees to monitor how likely an Artificial Fluctlight is to break the Taboo Index, but, after this parameter was discovered by Quinella, she used it to find humans who were skeptical of the Taboo Index and posed a threat to her rule.[3]


Sacred Arts[]

Main article: Sacred Arts

«Sacred Arts» (神聖術, Shinsei-jutsu?) are System Commands in Alicization that residents of Underworld believe to be magic rituals. In reality, they are just words used to arrange thoughts and guide the emotions of the caster to make use of one's imagination power. Because of this, the imagination of the user may either improve or decrease the effectiveness of an art.[9]

Secret Moves[]

A list of all known Sword styles and their Secret Moves can be found at: Sword Skills

«Secret Art Finishing Moves», usually shortened to just «secret moves», is the name that Underworld residents have given to Sword Skills existing in Underworld. It is currently unknown how these skills were implemented in Alicization, as ALO, which uses a complete copy of the SAO servers, is the only game that has the data for Sword Skills, since «The Seed» package does not include them.

Secret moves work quite similarly to the Sword Skills in SAO. A Secret Move is activated by assuming a certain stance with one's weapon, called an opening motion, which triggers the activation of a certain pre-programmed move which cannot be stopped midway. However, one major difference between Secret Moves and Sword Skills is that the highest possible consecutive hit combo of a Secret Move, unlike Sword Skills in SAO, is limited by the wielded sword's priority. The priority of wooden swords that are used for practice in the Master Sword Academy and tournaments seems to be enough for only 2-hit moves, while «Divine Instrument» class weapons with a priority of 45-46 allow up to 4-hit moves to be used. However, the residents of Human Empire only use 1-hit skills, because they do not believe that more than one is possible, until Kirito employs multi-hit skills.

Fluctlight Replication[]

When a male-female couple, who have registered a marriage in the system by pledging their marriage to the god Stacia in a ceremony conducted by the village chief (or, after churches were established, monk or nuns in the churches), have sexual intercourse, there will be a certain probability for a new Fluctlight model to be loaded into an empty cube within the Light Cube Cluster, with a part of the parents’ external elements and their patterns of thoughts and character inserted, forming a newborn baby after a period of pregnancy.[10]

Incarnation (Skill)[]

Incarnation (心意, Shin'i?) refers to a secretive art within the Underworld which enables an individual or group to alter the state of the world through imagination and will. It is a skill passed down to Integrity Knights since ancient times. However, only several Integrity Knights are able to use this skill.[11]

Server and Mainframe Composition[]

A LightCube

To store the Artificial Fluclights and mnemonic visual data of the Underworld, a powerful quantum computer, «Quantum Particle Gate Crystallization», also known as «LightCube» was created. The LightCube, measuring five centimeters in construct is made from Praseodymium crystals, capable of housing hundreds of millions of qubits of data, makes it possible to store the data of a Cloned Fluctlight.[1]

The mainframe of the Soul Translator comprised of a cluster of hundreds of thousands of systematically arranged LightCubes, each storing a single Fluctlight, are connected to a center of a massive cube that stores the extensive «Mnemonic Visual» data of the Underworld residents.[12] The Cluster — measuring three meters each side — is covered by a metal shell, which makes the cluster look like a simple rectangular box.[12]

The LightCube, located in the middle shaft of the Ocean Turtle is connected to two STL machines on the upper shaft and two more on the lower shaft, while the original STL prototype in Roppongi is connected to the LightCube via satellite.[13]


  • The name Alicization was likely intended to be a reference to "Alice in Wonderland".
  • After Rath's satellite network was disconnected, the IP address, which was obtained from an encrypted message sent to Alice anonymously, could be used to connect to Underworld from outside the Ocean Turtle.