Captains

History
While the history of the Gotei 13 remains largely unknown, the organization is lead by Yuki Tsunayashiro, who has stood at the head of the group since the death of Captain Hasako Nagasaki

The first generation of the Gotei 13 consisted of Yuki, Kenno, Katsuma, Orga, and 9 other captains

General Operation
The Gotei 13 does not normally operate as a cohesive unit. The command of the divisions are generally left to the discretion of its particular captain, who commonly runs it whatever way they see fit, allowing for the change of a division's traditional duties to an entirely new set and even the creation of a separate institution connected to the division.

The only general authority to call forth a combined front is from Yuki or Coconut

Unless specifically ordered by the Captain-Commander, captains can choose whether or not to attend meetings (at their own risk) or not even involve themselves in the daily situations of Soul Society. Captains are not allowed, without permission, to carry out activities outside of their normal jurisdiction or their division. The captain of one division cannot punish the subordinates of another captain.

Structure
The Gotei 13 is made up of thirteen divisions, with several divisions having certain specializations.

The Gotei 13 is led by the Captain-Commander, who has the statuary authority to conduct all the affairs of the Gotei 13.

Captain's Council
The captains congregate in the main hall of the First Division Headquarters to discuss important issues involving their specific divisions and matters which affect Soul Society. This council is highly formal, with the captain-commander leading its proceedings. All captains are considered equal (with the exception of the captain-commander), and determine the course of their individual division unless dictated otherwise by the captain-commander. Votes are carried out via a unanimous consensus.


 * The Coconut is the supreme leader of the Gotei 13.

Captains are generally the most respected Shinigami within the Soul Society, with the leaders of the Kidō Corps and Onmitsukidō possibly being of equal status. All captains are able to utilize the final stage of their Zanpakutō, and are far more powerful than even their lieutenants. Knowing Bankai gives captains an average of five-to-ten times the strength of Shinigami who are unable to perform it. They have extensively trained, if not mastered, their Bankai, allowing them to use the enormous power effectively in battle. Most captains have extensive knowledge of Shinigami history and battle tactics. All of these factors create a vast power gap between captains and lower-ranked officers. Except Orga

The true power of Soul Society lies in the captains of the Gotei 13, as they are the leaders of its military arm. With them at full strength, Soul Society is safe and almost unbeatable. If they are broken, their strength dwindles, making them highly vulnerable.

There are three different ways to become a Gotei 13 captain:


 * 1) Captain Proficiency Test: A test which requires the ability to perform Bankai. Nearly all Shinigami become captains using this method. At least 3 existing captains, including the Captain-Commander, have to witness the test.
 * 2) Ask Coconut: You have a high chance of getting accepted.
 * 3) Trial by Combat: To defeat a captain in one-on-one combat with at least 5 captain witnesses. This method is seen as being the exceedingly rarest and the least refined of the three. The method is commonly looked down upon by some captains as barbaric compared to the other refined methods. This method allows one to bypass having the mastery of Bankai or other possible abilities which a captain would otherwise be required to have knowledge of, for it allows no judgment from captains who would require those skills as a prerequisite to join their ranks.

Lieutenant
Lieutenants function as executive officers for their division, taking care of or supervising day-to-day operations. Along with their captains, they are not assigned to one specific squad. They generally only know the Shikai of their Zanpakutō but they are still the second strongest in their division. In the case of a division captain's death, departure, or other circumstances making them unable to perform their duties, the lieutenant acts as the "substitute captain" until another can be assigned.

Seated Officers
Seated officers are the remainder of the officers in the Gotei 13 which hold ranks at or below 3rd Seat. Captains and lieutenants have the ranks of 1st and 2nd Seats, respectively. Next to that, there are 18 more seats (3rd-20th).

Transferring to Another Division
Officers do not necessarily serve in their assigned division for life. It is customary to be transferred to another division after gaining some experience, an event which often coincides with a promotion.

Size and Recruitment
Each Division is made up of just over 200 Shinigami, with the Gotei 13's standing force being just around 3000 total enlisted troops. The Shinigami are typically recruited through the Shinigami Academy, but it must be noted not all graduates make it into the Gotei 13. Graduates from the Academy are required to take an entrance exam for the Gotei 13, and only those who pass are allowed to join. This exam can be taken multiple times.

Trivia

 * The Gotei 13 is referred to as the 13 Court Guard Squads in the English dub of the anime.