solitary confinement in a dark cell without bedding (up to one week)
A severe disciplinary punishment in Japanese prisons, involving isolation in a dark, bare cell for up to seven days.
Solitary confinement in a dark cell without bedding is considered one of the harshest punishments within prisons.
Compound of 重 (heavy, severe) and 屏禁 (confinement, isolation). The exact historical derivation is uncertain, but the term is used in modern Japanese prison regulations.