Riki-Oh: Toukatsu Jigoku
English name: Riki-Oh: The Wall of Hell
Genres: Action
Type: OVA, Episodes: 1
Aired: Jun 25, 1989
Studio: Magic Bus
Source: Manga
Rating: R - 17+ (violence & profanity)
Synopsis:
A Retelling of the prison arc of the manga RIKI-OH!

The story follows Saiga Riki-Oh, a young man blessed with inhuman strength. After taking revenge against a yakuza boss who was responsible for the death of his girlfriend, he ends up in a maximum security prison owned by a private organization. 

The prison is divided into four blocks, each run by a member of prisoners known as the Gang of Four. The first member is a tattooed knife wielder known as Hai that runs his block in a mafia style family system.  The second member is a giant man (known as Tarzan in the live action) with incredible strength.  The third member is a effeminate fighter named Huang Chaun that is growing Opium in the prison.  The final member is a small man that use sewing needles as his weapons.