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Aincrad viewed from a distance.

Sword Art Online (ソードアート・オンライン, Sōdo Āto Onrain?, abbreviated as SAO) is the first ever VRMMORPG produced by Argus for the NerveGear, with Kayaba Akihiko as the development director. The online game takes place on a hundred-floor floating castle called Aincrad.


Prior to official launch, «Sword Art Online» Closed Beta was available to 1,000 beta testers for a one month period from August to September 2022. During that period, «Sword Art Online» was lauded as an incredible experience, and it received extremely positive reviews despite the actual difficulty of the game. After the Closed Beta Testing ended, the Beta Testers were given the opportunity to pre-order the game.

Hardcore gamers, having waited three days in line to receive the much-anticipated first issue of Sword Art Online

Only 10,000 copies were printed in the first batch of the game, and online sales sold out within seconds. Hard-core gamers waited in line for days to purchase the first few hard copies from many stores.

«Sword Art Online» officially started server service at 13:00 on November 6, 2022 and obtained infamy when the creator succeeded in trapping 10,000 people in the game, and making it so that death in-game would mean actual death for the player. During the two-year period the game remained active, «Sword Art Online» evolved into an innovative yet complex society of individuals with mixed feelings about the possibility of clearing the game.

Psychologically, many players experienced extreme despair, grief, insanity and sadness during the course of the death game. Of the total 3,853 deaths, over half occurred in the first month of SAO. Combined with lethal dungeon traps and bosses, Player Killing (PKing), crime, suicides, a slowly dwindling population, and increasing difficulty on the higher floors, the prospects generally looked very bleak.

The game was prematurely ended on the 75th Floor, instead of the intended 100th Floor, when the final boss, Heathcliff, revealed to be Kayaba Akihiko himself, was defeated in a duel against Kirito.[1] A total of 6,147 survivors were supposed to be logged out from it at 14:55 (Aincrad Standard Time) of November 7, 2024.


The game operates similar to most MMORPGs with a level system and eventual skill mastery with some limits placed on it. The entire game is monitored and maintained by the «Cardinal System», which self-corrects any problems.

While the Sword Art Online mainframe is capable of incredible graphical and rendering capacities, it does not actually render the entire environment in full detail unless a certain region is specifically observed by a player. SAO uses a «Digital Focusing System», which brings out the finer details of an object only when a player shows interest and focuses their visual field on it. This reduces the strain on the SAO mainframe processor, which, despite its high performance power, is incapable of rendering all marginal details of the environment simultaneously. This effectually produces the illusion that the SAO graphical and VR experience is incredibly detailed. However, the SAO mainframe has a difficult time rendering the sensation of water in baths or showers.

Virtual Reality Experience

As a complete virtual reality MMORPG, the SAO system is capable of rendering the entire Aincrad environment with incredible realism. By stimulating nerves in the brain, it is possible to taste food, feel the wind and weather, move one's body, and live in SAO as if it were an alternate reality. However, there are several major differences that set the Sword Art Online environment apart from the real-world experience.

First, no pain is actually felt in any situation. As a result, players can undergo severe injuries and still only feel an uncomfortable tingling sensation. Second, there is no blood; in its place are red virtual gashes that are seen in the place of injuries. Third, Sword Skills allow attacks to be performed with normally impossible speed, dexterity, and power, based on the player's stats. Fourth, there are some everyday actions that simply are not done in the SAO world, such as changing clothes by hand or attempting to wield two items at the same time.

While playing Sword Art Online, players still feel fatigue and hunger, regardless of the state of their actual bodies. As a result it is an absolute necessity for all players to eat and sleep within the game; however there is never a need to go to the bathroom.

Death or deletion in the game is visualized by fragmentation into thousands of polygon shards. All monsters, items, and players that have their HP or durability reduced to zero, disappear and fragment into polygons in such a fashion.

The SAO system generally censors mature content, such as sexual intercourse, but it is possible for players to disable the censor if «Moral Code Removal» is selected in the options menu. Selecting this option also temporarily increases the quantity of tactile data, but this effect only manifests itself when all the equipment of a player is removed.[2]


Global Setting

The sunset at Aincrad's 1st Floor.

Sword Art Online is set in Aincrad, a floating castle of 100 floors. At its base, it is approximately ten kilometers in diameter, and it is completely rendered in all dimensions. Because of the nature of Aincrad as a floating castle, there are no invisible barriers or no-access regions at the edges of the map. Aincrad's perimeter is merely surrounded by guard rails that can be jumped off of, but any player doing so will be deemed as dead after two minutes of falling.

Each individual floor has its unique climate, geography, fauna, and environment. However, each floor shares the principle of having a Labyrinth Tower that connects to the next floor, as well as the principle that the top of each tower is guarded by a Floor Boss, which has to be defeated before players can advance to the next floor. Some floors are known for being fairly cold, while others are known for flowers and forests. Most floors on Aincrad have a theme.

Seasons and Weather

Sword Art Online has its own «Aincrad Standard Time»[citation needed], and its own «Aincrad Calender» with specially named months. Known calendar months include:

  • «Month of the Sakura» (サクラの月, Sakura no Tsuki?, April)[3]
  • «Month of the Ash Tree» (トネリコの月, Toneriko no Tsuki?, October)[4]
  • «Month of the Cypress» (イトスギの月, Itosugi no Tsuki?, November)[5]
  • «Month of the Holly» (ヒイラギの月, Hīragi no Tsuki?, December)[6]

Globally, Sword Art Online has seasons and weather settings that are effective throughout the floors. Aincrad's season correlate with the seasons of the real world, but they are generally much milder. As a result, it is not always snowy in the winter, or scorching hot in the summer. Weather settings are generally random and quite realistic.

Physical Surroundings

In Sword Art Online, physical surroundings such as walls, buildings, monuments, and major features are considered "Immortal Objects". An error beep and a notification will sound if immortal physical objects are struck, even if by accident.

SAO immortal object.png

All non-immortal objects have a «durability» value. Durability is an important feature of Sword Art Online, and is a measure of how much an item or object has been used (similar to HP), and how much it will last before it expires and shatters into polygon fragments. Clothes, equipment, weapons, potions, crystals, and food are all subject to gradual loss of durability.

Oftentimes, players must invest significant resources into repairing and buying equipment. Many characters carry extra back-up weapons into dungeons (Asuna in Aria in the Starless Night carries five rapiers in her inventory due to durability concerns in solo dungeon-hunting), others rely on merchants and smiths who regularly repair and upgrade equipment. Food always declines in durability with respect to time, and freshly prepared foods will disappear if not eaten soon enough. Merely dropping food can cause food to lose its durability and fragment into polygons.


Initiation and Character Creation

Logging onto «Sword Art Online» is done by using the voice command «Link Start» after powering-on NerveGear hardware. A brief few seconds of tunnel-vision colors are seen while the NerveGear intercepts signals from the player's brain, before the powerup screen is seen. A pre-game status check then confirms the link connection of the five senses: touch, sight, hearing, smell, and taste. Upon logging on, a language-select is prompted, and then the login screen appears. After a welcome screen, a bright light ensues and the player can begin creating their character.

The first time a player utilizes NerveGear hardware, he or she is prompted to touch various parts of the body in order to calibrate the machine. While players were given an option to choose their in-game appearance however they liked (gender, height, girth, etc.) at first, the game avatar customisation feature was removed when Kayaba Akihiko made an announcement during the first day and changed everyone's physique to their real-world appearances, though the option to customize their eye color, hair color and style remained.

User Interface

Visual Interface

Hit Point Bar

In a player's display, without accessing any skills, one can see several interfaces.

The hit point bar is located on the upper left corner of one's field of vision. It displays the player's name, a visual hit point gauge, along with numerical hit points (current/maximum), and level. It also shows the hit points and names of all other members in the player's party in a smaller bar.

A clock displaying Aincrad local time can be seen in the bottom left corner of the visual field.

A Color Cursor can be seen over every NPC, monster, and player in the game. This cursor is either green (for players), orange (for players with criminal infractions), yellow (for NPCs), or various shades of red (for monsters). During battle, the health bar of monsters can be seen around the targeted enemy, as well as the name of the monster. Bosses typically have multiple health bars. As for a monster that level is too far apart, hit point bars of that monster will be unable to see and instead indicated with 'unknown'.

Touch Interface

Players can interact with the environment by tapping various key objects, including door knobs and items. Doing so either performs the default function, or brings up a floating dialogue that has several options, similar to the "right-click" on a PC.

In Sword Art Online, the Touch Interface replaces many actions and simplifies the process of actually performing an action. For example tapping on a jar of cream to "use" the cream. Tapping again on bread automatically spreads the cream on the bread.[7]

Main Menu Window

SAO's Menu Interface.

The main menu is the primary means of accessing a player's items, maps, skills, and inventory. The menu window can be summoned with the player's right hand by extending its index and middle fingers together and swinging them downwards in a straight line, parallel to the axis of the player's avatar. Due to the strict motion requirements, it may be difficult to summon from a supine or lateral decubitus position. Hence, it is recommended to perform the gesture command from a standing position.[8]

Once the gesture command is performed, a ringing sound is heard and the menu appears. In the novel, the menu is a shining purple rectangle window, while in the anime, the main menu has a white layout, and is structured with the summary diagram on the left, circular category buttons in the middle, and the detail dialogue to the right. There are five category options: inventory/equipment, friends/guild, Communications, maps/quest, Settings. These five category icons scroll, and the category being accessed moves to the top.

  • Inventory/equipment:[citation needed] The icon for the category is a character icon. This is the default screen when opening the Menu interface. The left screen is an image of the body, with multiple points that allow the gamer to equip items or clothes. The right screen has three sub-menus:
    • Equipment:[9] Selecting this sub-menu will open another three sub-menu:
      • Weapons:[citation needed] The icon for this category is a sword like the one used in Equipment.
      • Equipped:[citation needed] The icon for this category is a piece of armor.
      • Accessory:[citation needed] The icon for this category is a necklace.
    • Items:[9] Selecting this sub-menu will open an additional scrolling screen on the left that lists all items. When an item is selected, it materializes in front of the player. The inventory turns red when a player has too many items.
    • Skills:[9] Selecting this sub-menu will open additional scrolling screen on the left that lists all skills of the player.
  • Friends/Guild:[citation needed] The icon for the category is two character icons together. The right screen has three sub-menus:
    • Party:[10] Selecting this sub-menu will open three additional options. The first is «Create» (作成, Sakusei?), the second is «Invite» (招待, Shoutai?), and the third is «Dissolve» (解散, Kaisan?).[11]
    • Friend:[10] Selecting this sub-menu will reveal a list of a player's friends. Selecting a single friend will produce three additional options: «Message Box», «Position Check», and «Profile».[10] The names of fallen friends turn grey, disabling the ability to contact them.[12]
    • Guild[10]
  • Communications (コミュニケーション, Komyunikēshon?):[13] The icon for this category is two chat box icons together. The icon flashes automatically whenever a player receives a message.[14] Messages cannot be sent to a player who is currently in dungeon.[15]
    • Befriend:[citation needed] This option allows the player to send a friend request to another player. The other player is added to the Friend List if the request is accepted.
    • Trade[citation needed]: This option opens a trade window with another player. Trading can be used just to show another player items, or complete a trade after both parties accept the offers put forth.[citation needed]
    • Duel[citation needed]: This option allows the player to send a Duel request. The player being challenged has the privilege of selecting one of the available duel modes.
    • Marriage:[13]This option, located at the very bottom of the Communications category, allows the player to send a marriage request to another player. Married players have uninhibited access to the other's equipment window, and their inventories are merged.[16]
  • Maps/Quest: The icon for the category is a balloon location icon. The right screen has three sub-menus:
    • Dungeon Map:[17] Selecting this sub-menu will reveal a map of the dungeon that the player has explored.
    • Quest:[17] Selecting this sub-menu will open the player's quest log, which displays information on current quests and their progress.
    • Field Map:[17] Selecting this sub-menu will reveal a map of the floor that the player has explored.
  • Settings/Main menu: The icon for the category is a gear. The right screen has three sub-menus:
    • Option[18]
    • Help:[18] Selecting "Help" will call a GM (Game Master) in the left screen.
    • Logout:[18] The logout button was disabled as of the first day of the official SAO launch. Consequently, the left-screen is also completely blank.


A number of equipment exists in Sword Art Online, including armors, weapons, and so on. Players can equip them on over ten different parts of their body, including the left and right hand, head, arm, body, wrist and so on.[19]

Equipment in SAO can be divided into two groups: «Player-made» and «Monster-drops».[20] Player-made equipment were usually the better of the two, but even a few rare monster-drops rivaled their counterparts. However, there also exists a third group of equipment, which included those that are purchased in NPC shops.

Level System

SAO uses a level-based system to determine the strength of a player. Once the player gains enough EXP, their avatar glows a golden hue, and their current level is raised by one. Three stat points are awarded at each level-up, which the player can use to raise either their STR attribute or their AGI attribute.[21] SAO did not have a level cap at the time it was cleared, though had the game continued and a cap was needed, the Cardinal System would have generated one.[22]

As for the near-unlimited number of Skills within SAO, the skills have to be utilized in order to be leveled up.[citation needed] After reaching a skill level of 1,000, that skill is said to be «complete» and cannot be further leveled.[23] Sometimes, while training a skill, other skills could be unlocked, such as the necessity of training the «One-Handed Sword» skill in order to unlock the «Two-handed Sword» and «One-Handed Rapier» skills.[citation needed]



Several factors go into the calculation of damage in Sword Art Online. Among them include the efficacy of hits (a direct hit as opposed to a scratch), the skill level of a player, the Sword Skill used, and the weapon's stats. SAO's damage calculation system is more complicated than the system in ALfheim Online.

Weapons have the following enhancement parameters that determine stats: Sharpness, Quickness, Accuracy, Heaviness, and Durability. When a weapon is given to an NPC or player smith to upgrade, bonuses such as +1 or +2 are appended select categories. Players use an abbreviated notation to describe the effective bonuses on a weapon. «1A2H1D» for example, has +1 Accuracy, +2 Heaviness, and +1 Durability.

On a regular basis, these parameters cannot be seen unless a weapon is «Appraised». Selecting a weapon will only show its name and its aggregate bonuses (the sum of all enhancement parameters). For example, Kirito's «Anneal Blade +6» has the parameters «3S3D».

Status Effects

Main article: Status Effect

Status Effects, like many MMORPGs, play an important role in combat. Many attacks have a random chance of dealing status effects. They are generally not curable, unless the appropriate Crystals are used. Most status effects expire after a set period of time.

Monster Battle Mechanics

Frenzy Boar HP Cursor.png

There is no «Magic» in SAO except for the different colored crystals that bring instant effects. Instead players can fight using their «Sword Skills». Execution of Swords Skills are assisted by the system, and it can fall into any of the four properties: Thrust, Slash, Pierce and Blunt. SAO has no projectile weapons, with the exception of Throwing Picks, darts,[24] boomerangs[24] and chakrams.[25]

Attempting to battle without Sword Skills is largely ineffective, and it is equivalent to waving one's sword around without doing damage. Many beginners make this mistake, and they can lose a large portion of their health if they panic and forget to use their Sword Skills.[26]

Battle Results

Defeating a monster brings up a Congratulations screen with a summary of results: EXP gained, Cor gained, and Items dropped. Distribution of loot occurs automatically, and Cor is automatically divided evenly between the party/raid members while items are placed in the inventory of the person who receives it. Unlike the systems of many MMOs, Sword Art Online does not have a battle log or announce to others what items other players receive. As a result, Boss Battles can end awkwardly as there is no fair mechanism of splitting the loot among the victors. To prevent disputes, guilds often have set policies dictating the division of loot.

In Boss Battles, being the player to deal the finishing Last Attack produces a rare drop for the individual player.

In general, monsters cannot enter safe zones, such as towns or cities.

Party Battle Mechanics

It is generally much more efficient to battle in parties. While there are less emphasis on Classes in Sword Art Online, and monsters can only be engaged by one player at a time, the main benefit of battling in parties is the ability to «Switch».

Switching allows a fellow party member to take the lead spot against an opponent at any time. Most monsters and bosses have a short down-time in between attacks, so switching during the gap allows an additional blow to be dealt when a monster is stunned. Additionally, the AI algorithms are known to run slower when a change of attack style (which occurs during a switch), so monsters have marginally slower reaction times immediately after a «Switch». Kirito mentions that «Switch» is one of the skills that are improvised by players without the assist of the system, also dubbed by Kirito as "a skill outside the system".

The maximum number of players that can form a party is six. Eight parties (or groups) constitute a complete Raid Group large enough to challenge bosses.

Player vs. Player Combat

In Sword Art Online, it is possible to engage in combat with other players. Player vs. Player combat can either be authorized or unauthorized.

Unauthorized combat can be initiated by simply striking another player intentionally. This will render the aggressor's cursor icon as orange, which is visible to everyone for several hours (repeated offenses will render a player's cursor permanently orange). While anyone can be challenged in unauthorized combat, such player vs. player battle cannot occur in safe zones. Attacking a player in a safe zone will not decrease HP, but the recoil and impact of Sword Skills can be felt.

A duel between two players.

Authorized combat is essentially dueling. It is done by requesting permission from another player to engage in a duel. There are several different duel modes, which vary conditionally by concluding after the first clear blow, after HP decreases by one half, after a period of time, or death. Attacking someone during a duel will not turn any participant's cursors to orange.

Like most MMORPGs, Player Killing (PKing) is often a result of unwanted player-player combat. While death in the original Closed Beta test resulted in respawning in the Room of Resurrection on the 1st Floor, player death is permanent and real in the Official Server Service. As a result, PKing in Sword Art Online has a severity akin to murder.


  • When the Sword Art Online VRMMORPG game was first sold, it had a recommended age rating of 14+. However, there were players who were below the recommended age rating on the first day of the official SAO service, such as Silica, who was twelve at the time, or the children at the church in the Town of Beginnings.
  • During the SAO Incident, the Sword Art Online servers were used by RECT Progress Inc. to create ALfheim Online.
  • SAO only allows for English alphabet to be used for names, therefore all players use English or romanized names.
  • Heathcliff revealed that he had acquired a lot of inspiration from a game called Wizardry.[24] It is likely that this inspiration had an impact on the development of Sword Art Online.
  • In the web version of the story, 50,000 players were trapped in the game. This number was reduced to 10,000 in the published novel.