The Central Great Underground Prison consists of eight levels, in which the Central 46 decides which the criminal Shinigami would be confined, depending on the severity of his or her crimes. The prison is located underneath the barracks of the First Division.
3rd Level: Shugō
Shugō (衆合, Samghata) is the third level of the underground prison and reserved for those who used forbidden Kidō techniques. Tessai Tsukabishi was to be given a life sentence in this level for using the forbidden Kidō spells Jikanteishi and Kūkanten'i.
8th Level: Muken
Muken (無間, Avici) is the eighth and final level of the underground prison. Sōsuke Aizen was sentenced to 18,800 years in this level for high acts of treason and a long list of other crimes. His condescending remarks during his trial raised the sentencing to 20,000 years.
Muken is a voided space completely sealed off from the outside world, aside from the main tower that serves as the entrance and exit. The realm stretches on infinitely. Under normal circumstances, non-criminals are not permitted entrance, but Retsu Unohana managed to gain permission from Captain-Commander Shunsui Kyōraku to use the location as a battlefield to train Kenpachi Zaraki in Zanjutsu. Muken is reserved for criminals whose heart cannot be stopped by any means by executioners (i.e. those who are immortal).
When Shunsui went to visit Aizen in request for his assistance against the Wandenreich, he had the key to Muken sealed into his chest; if he be killed, the gates to the outside world would be sealed off, preventing Aizen's escape. Aizen himself is bound by seals in the form of black straps, which could be undone by 19 keyholes on the ground; Shunsui was given permission to use up to three keys.
- Bleach manga; Chapter -97, page 10
- Bleach manga; Chapter 423, pages 1-4
- Bleach manga; Chapter 510, pages 8-9
- Bleach manga; Chapter 523, pages 9-12
- Bleach manga; Chapter 623, page 5
- Bleach manga; Chapter 618, page 4
- Bleach manga; Chapter 617, page 12
|Human World||Kagamino City · Karakura Town · Karakura High School · Karakura Hospital · Kurosaki Clinic · Urahara Shop · Bount Mansion · Naruki City · London|
|Soul Society||Rukongai · Seireitei · Soul King Palace · Central 46 Compound · Nest of Maggots · Shin'ō Academy · Sōkyoku Hill · Gin Tonbo · Kuchiki Manor · Central Great Underground Prison · Wandenreich City · Silbern · Wahrwelt · Western Branch · Reverse London|
|Hueco Mundo||Forest of Menos · Las Noches · Negal Ruins|
|Others||Hell · Dangai · Valley of Screams · Garganta|
|Combat||Zanjutsu • Hohō • Kidō • Hakuda|
|Abilities||Zanpakutō • Reiryoku • Reiatsu • Reiraku • Konsō • Shunkō|
|Government||Soul King • Central 46|
|Nobility||Kuchiki Clan • Shihōin Clan • Noble Houses • Kasumiōji Clan • Ise Clan • Tsunayashiro Clan • Formerly: Shiba Clan • Ryōdoji Family • Dark Ones|
|Military||Gotei 13 • Onmitsukidō • Kidō Corps • Royal Guard • Gatekeepers|
|Institutions||Seireitei Communication • Shinigami Research and Development Institute • Shin'ō Academy|
|Recreational||Shinigami Women's Association • Shinigami Men's Association • Tea Ceremony Club • Ikebana Club • Calligraphy Club|
|Locations||Soul Society • Seireitei • Central 46 Compound • Nest of Maggots • Sōkyoku Hill • Gin Tonbo • Kuchiki Manor • Central Great Underground Prison|
|Items||Jigokuchō • Gigai • Reigai • Gikon • Modified Soul • Denreishinki • Ōken • Gokon Tekkō|