Gotei 13

The is the organization which most shinigami join. It is split into thirteen divisions (hence the name), with several divisions having certain specializations. The 4th Division is the medical/supply division, the 11th Division is the combat division (specialization in swordsmanship), and the 12th Division is the research/scientific division. It's unclear if the other divisions are specialized, as the three above are the only ones who receive any significant attention apart from their members.

Ranks
As with any army, the Gotei 13 has ranks. There are 20 ranks for officers but no ranks for non-officers. The lower the number is, the more important. The ranks and their descriptions are below, from highest to lowest in terms of strength.

Commander-General
The sōtaichō (総隊長, lit. commander-general, dubbed as head-captain) is the leader of the Gotei 13 and the captain of the 1st Division; the implication is that this is an ex officio or a primus inter pares position. The current holder of this title is Shigekuni Yamamoto-Genryūsai.

Captain
A is the leader of one of the thirteen divisions (with the special case of the Commander-General). A single Gotei 13 'unit' (隊) is estimated at about 200-500 troops. Viz renders the units as 'companies' rather than 'divisions' because captains lead companies in real life. However, given that each Captain in Bleach leads a major part of a military wing or corps, they could be division commanders or Generals. Most literally, the name simply means 'unit commander', which could be practically any officer rank.

Captains are generally the most respected shinigami in Soul Society, with the Central 46 Chambers, Demon Art Corps, and special forces leaders possibly being on equal status. With one exception (Kenpachi Zaraki), all captains are able to perform the bankai of their zanpakutō and are generally much more powerful than even their lieutenants. Knowing the bankai gives captains an average of five to ten times the strength of shinigami who are unable to perform it. They have also extensively trained, if not mastered, their bankai, allowing them to actually use the enormous power effectively in battle. Most captains are also skilled in the use of shunpō, kidō, and generally have excellent knowledge of shinigami history and battle tactics. All of these factors create a huge power-gap between captains and lower-ranked officers.

There are three different ways to become a Gotei 13 captain:
 * 1) To take the, which requires the ability to perform the bankai. Presumably, most shinigami become captains using this method. At least three existing captains, including the Commander-General, have to witness the test.
 * 2) To have personal recommendations from at least six captains and approval from at least three of the remaining seven.
 * 3) To defeat a captain one-on-one with at least 200 witnesses from the captain's division. Kenpachi Zaraki is the only known captain to have achieved his rank using this method.

Lieutenant
A is the 2nd seated officer in each division. Because captain describes the unit commander, vice-captain is the most literally accurate translation some have used. The Viz manga translation renders the rank as the similar but somewhat longer "assistant captain", while the English dub of the anime uses the term "lieutenant". Although this does not apply to modern armies, in historical real-life armies the lieutenant has been the adjutant of the captain, as is the case for fukutaichō and taichō in Bleach. Therefore, lieutenant is a correct real-life equivalent of this rank. Holders of this rank in Gotei 13 have also been called adjutants.

Lieutenants function as executive officers for their division, taking care of or supervising day-to-day operations. They (along with their captains) are not assigned to one specific squad. They generally only know the shikai of their zanpakutō, but are still the second strongest in their division. In the case of a division captain's death, departure, or other circumstances making him 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 who hold ranks at or below 3rd Seat. Captains have the rank of 1st Seat and lieutenants are 2nd Seat. Next to that, there are 18 more seats (3rd to 20th). These ranks are somewhat analogous to junior officers or non-commissioned officers in modern militaries. There seems to be a distinction between senior and junior seated officers, just like in real-life armies. In the Gotei 13, only one person can hold a senior officer rank (such as 3rd or 5th seat), but there are several holders of junior officer ranks (e.g. 20th seat). This may vary from division to division however, as there are two 3rd Seats in the 13th Division. Seated officers often lead subunits within each division (for example, Hanatarō Yamada is leader of 4th Division's 14th Advanced Relief Team).

Uniforms
Most Gotei 13 personnel wear the standard Shinigami uniform, called - a white kosode, a black kimono and hakama, and a white obi sash. Lieutenants sometimes also wear an armband which carries their division symbol and its number, usually on their left arm. They are required to do this when they are summoned to a meeting but apart from this it seems that it is rarely compulsory; at the time the series takes place, the use of the armbands was noted to have fallen out of fashion.

Captains wear a white haori over the usual black shinigami clothes, with the number of their division on the back, inside the Gotei 13 symbol (a rhombus). Those worn by senior captains have sleeves, while the others don't.

Gotei 13 officers, particularly captains and lieutenants, often customize their personal appearance or that of their uniform. Some of these modifications include:
 * Captain Soifon of the 2nd Division wears a sleeveless and backless shinigami outfit (when she's fighting) under her haori, which is standard issue for the head of the special forces. She also wears a yellow sash a layer above, but slightly lower than her white one.
 * Captain Retsu Unohana of the 4th Division wears an obi sash rather than a standard one.
 * Captain Byakuya Kuchiki of the 6th Division wears an extremely expensive scarf named ginpaku kazahana no uzuginu and a white ceremonial hairpiece symbolizing his noble lineage.
 * Captain Sajin Komamura of the 7th Division wears shoulder guards over his haori and large gloves which goes up to his arms. He also wore a helmet to hide his appearance. He later removed the helmet.
 * Captain Shunsui Kyōraku of the 8th Division is probably the most flamboyantly dressed of the captains, always seen wearing a straw hat and a gaudily-colored haori over his uniform.
 * Captain Kaname Tōsen formerly of the 9th Division wears an orange scarf with his outfit, a sleeveless keikogi as well as white boots.
 * Captain Tōshirō Hitsugaya of the 10th Division wears a green sash pinned with a star around his shoulder to hold his sword.
 * Captain Kenpachi Zaraki of the 11th Division wears a jagged edged haori, which was taken from the previous captain.
 * Captain Mayuri Kurotsuchi of the 12th Division wears a bloated purple cravat and a hat decorated with two horizontal spikes.
 * Lieutenant Chōjirō Sasakibe of the 1st Division wears a jinbaori over his shihakushō.
 * Lieutenant Shūhei Hisagi of the 9th Division wears a sleeveless keikogi and black choker.
 * Lieutenant Rangiku Matsumoto of the 10th Division wears a top that is deliberately loose and hangs open to reveal her ample bosom. She also wears a pink scarf (or stole), and wears her lieutenant's badge around her waist with her sash, tied in a bow.
 * Lieutenant Nemu Kurotsuchi of the 12th Division has a very abbreviated outfit: the hakama is absent, leaving her with a mini-skirt version of the kimono that is belted at the waist.
 * All known members of the 9th Division wear keikogi without sleeves, including the captain.

Insignia
Each of the 13 divisions in Gotei 13 have their own symbol that represents the division's primary role, which all seem to be based on flowers. When a power limit is placed on a captain or lieutenant, their symbol appears on a certain part of their body until the limit is lifted. Each symbol also has a specific meaning, but not all of them have been revealed. The 11th Division symbol means 'fight' while the camellia symbol of the 6th Division means 'noble reasoning'.

Captain and Lieutenant listings
Below are the names of all Captains and Lieutenants in the Gotei 13.