Violating the least rule results in "solitary confinement", which is not just being left alone in a room like in the United States. In Japan the little room, which is more like a closet, has some metal loops in the wall. They strap this leather and metal straight jacket thing on you and hook you up to the rings. The belt is wide and can be tightened against the disobeying prisoner's abdomen so that they can only take very shallow breaths. Apparently it is extremely uncomfortable. During meal time (once a day) you get a bowl of soup. Naturally the victim, err prisoner, is not released from the "protective restraints". They just unhook the prisoner from the wall, lay them down by the bowl of soup which is placed on the floor and they lap it up like a dog. Afterwards the prisoner is lifted and hooked up again. They stay in that condition for the term of the solitary confinement, anywhere from 2 to 10 days, depending on how much the prisoner pissed off the guards. There are no bathrooms, of course, so the prisoner just shits his soup diarrhea on himself.
The main human interaction in Japanese prisons, solitary confinement and otherwise, is a guard bitch slapping you and screaming in your face what a worthless piece of trash you are.
is this a first hand information or just an urban legend?
i dont think this is happening or else U.N. may step in for humanitarian reasons