Introduction to Sovereignty Mechanics

The following is an introductory guide to the basics of sovereignty mechanics in EVE Online. This content is adapted from an article published originally on the EVE news site, Crossing Zebras. I wrote the original article in April of 2016, but it has since been lost, as CZ relaunched their site shortly thereafter and did not convert all of their prior content to the new format. I have preserved the original text here, for those who are seeking a general understanding of this important aspect of EVE Online's gameplay in null security space.

Last updated: June 26, 2016

In the spring of 2016, “World War Bee”, the great conflict between Imperium forces and the loose alliance of opposing organizations known as the Money Badger Coalition (MBC), began in the northern regions of null security space. This war was so large, with many tens of thousands of players involved, that even non-gaming media outlets reported about it.

In the early stages of the war, all combatants spun their propaganda machines at full speed, making it difficult to discern who was actually winning. In truth, most of the interested observers of the war did not understand the mechanics upon which it was based. The news reports about World War Bee spoke of timers and I-Hubs and TCUs and Entosis Links and Vulnerability Windows – it was all very confusing for those unfamiliar with the details of war in 0.0 space.

This kind of confusion about how war really works in 0.0 space remains common. As ownership of systems changes in null-sec space, the uninitiated often wonder: what does it all really mean?

Sovereignty changes often in 0.0 space. Maps for tracking the ebb and flow of system ownership can be found at

Sovereignty changes often in 0.0 space. Maps for tracking the ebb and flow of system ownership can be found at

Intro to Aegis Sov

In the spring and summer of 2015, CCP Games rolled out a series of dramatic revisions to how player alliances control and hold sovereign territory in null-sec space. The most significant parts of these revisions were released in the Aegis update, so the current sovereignty system is officially called “Aegis sov”. (Note: the blog posts announcing these changes were authored primarily by developer CCP Fozzie, so some players refer to the current system as “Fozziesov”.)

“Holding sov”, as it is generally known, provides the owners of a system, and their approved allies, with improved returns for their activities in that system. Occupying the system and actively conducting military and industrial operations there also provides special bonuses that make the system more defensible against invaders. Perhaps more importantly, in addition to these advantages, holding sov also provides the psychological benefit of “planting a flag” in a null-sec system, and thus declaring: “This space belongs to us. Try to take it only at your peril.”

Planting the Flag: the TCU

Territorial Claim Unit (TCU)

To plant that flag of ownership, a player alliance must deploy a Territorial Claim Unit (TCU) near a planet in a system. There can be only one TCU deployed in a system. The owner of the TCU is listed as the owner of that system on the game’s starmap.

In addition, all player-owned starbases (POS structures) in the system that are owned by the TCU’s player alliance get a 25 percent reduction in fuel consumption.

Developing a System: the I-Hub, System Indices, and ADM

To improve a system and make it more valuable and defensible, owners can deploy an Infrastructure Hub (I-Hub), which allows the system to generate combat anomalies, ore sites and signatures more frequently. Players may then harvest rewards from these locations in the system and generate higher levels of income.

Infrastructure Hub (I-Hub)

I-Hubs also allow system owners to set up more advanced POS structures, such as Jump Bridges, which act like temporary stargates to nearby systems, and Cynosural System Jammers, which help to prevent others from entering the system through a back door in space-time from a remote location.

Each upgrade to an I-Hub requires a physical unit to be produced and installed. I-Hubs may be upgraded as system indices increase. The three types of system indices are:

  • Strategic Index: Automatically increases over a continuous period as an alliance maintains control of the I-Hub
  • Military Index: Increases in proportion to the number of non-player character (NPC) ships killed in the system, mostly in anomalies and signatures
  • Industrial Index: Increases in proportion to the volume of ore mined in the system

As the System Indices increase, they also contribute to an Activity Defense Multiplier (ADM) in the system, which affects how long attackers must wrestle with control structures like TCUs and I-Hubs in a system. The higher the ADM, the more time an attacker must dedicate for a successful attack.

Because of their vital importance in establishing control of a system and enhancing its defensibility, wartime attackers in null-sec focus mostly on capturing TCUs and I-Hubs. There also may be other structures in a system, including POSes and stations, which are important for providing safe harbors from which to stage operations.

Setting Windows in Time

Alliances influence when their systems can be attacked, to a significant degree, by setting a vulnerability window – this window can be set for each structure they control. The length of a vulnerability window is 18 hours divided by the ADM in the system, which produces windows ranging in length from 18 hours to 4 hours.

The vulnerability window allows an alliance to set ranges of time when they are best able to field a sufficient defensive force. This is a significant advantage for defenders of sov space.

Capturing TCUs and I-Hubs

One of the biggest changes in Aegis sov was the introduction of the Entosis Link, a ship module that affects structure control. During a structure’s vulnerability period, any player can fly within range and activate an Entosis Link on it. The alliance who owns the structure is notified of the attack so they can respond.

Depending on the ADM of the system, a successful Entosis Link attack can take anywhere from ten minutes to an hour, if the attack is uncontested. That last point is important, as it means that the defenders can activate one of their own Entosis Links on the structure, and thereby reset the time needed for an uncontested attack. For this reason, Entosis Link attacks often result in significant firefights, as each side tries to clear off any enemy ships that may interfere with their Entosis Link attacks.

Using Entosis Links can be tricky. A ship using an Entosis Link cannot cloak, warp, dock, jump, receive any form of remote assistance, or exceed a velocity of 4,000 meters per second. Additionally, as long as just one defender has an active Entosis Link on their structure, all attacking Links will be negated, no matter how many. The only limitation for defenders is that their allies cannot use Entosis Links to help defend their structure directly. From the structure’s perspective, any activated Entosis Link that does not belong to the defending alliance is an attacker.

Entosis Link capture mechanics

If the attackers are successful in completing an uncontested Entosis Link attack, the structure enters a reinforced mode, which ends at a random time within the structure’s vulnerability window, two days (48 hours) later.

When the structure comes out of reinforcement mode, a new phase in the capture process begins. Command Node anomalies then spawn at random locations throughout the constellation of that system. Players may then use Entosis Links to put the various Command Notes into reinforcement, as was earlier done to the structure itself. If attackers can successfully capture enough Command Nodes, they then win the attack on the structure, and the TCU or I-Hub explodes. Any alliance may then deploy their own replacement structure

Capture Process for TCUs and I-Hubs

Capturing Stations

For stations in a system, the capture process works the same as for TCUs and I-Hubs, but with two important differences.

First, after an attacker is successful capturing a sufficient number of Command Nodes, the structure does not explode. Rather, it goes into Freeport Mode for two days (48 hours) which means that anyone can dock in the station.

At that point, a second set of Command Nodes is generated at random throughout the constellation. The Alliance that captures enough Command Nodes becomes the full owner of the station.

Capture Process for Stations

Tracking War Progress

Aegis sov requires successful execution of a series of attacks and capture events for each structure in a system. How does an observer keep track of all the comings and goings, to see the ebb and flow of the war?

For the casual observer, these resources are very useful:

  • TimerBoard is a handy utility for tracking all of the various timers for TCUs, I-Hubs and Stations.
  • Dotlan keeps track of what systems are contested, and is useful for visualizing how the war is progressing.
  • Maps that illustrate current null-sec system ownership by alliance and coalition, as well as for factional warfare, can be found at

I’ve covered only the critical aspects of Aegis sov in this guide – there are many other details involved. But for those who just want to understand what is going on in null-sec space, the previous explanation should provide you with a sufficient awareness of the essential mechanics.

Fly safe! o7