A VISITOR from overseas can hardly fail to be struck by what a peaceable, law-abiding land Japan is. Crime rates are roughly a tenth of those in other rich countries. A wallet left on a train is handed in with scrupulous honesty. Gun crimes are nearly unheard-of, and even muggings are vanishingly rare. Neighbourhood cops often patrol the unmean streets with no more threatening an instrument than a sit-up-and-beg bicycle. Often the biggest headache seems to be shoplifting by Japan’s growing numbers of elderly.

For most criminals, the country’s justice system is remarkably lenient and focused on rehabilitation. Police and courts make every effort to keep first-time offenders out of confinement. Minor wrongdoers who confess and apologise are often allowed to go free with a stern warning. The state works with families to ensure that miscreants return to the straight and narrow. When young criminals are sent inside, it is to what resembles a strict boarding school more than a penal institution. Courts incarcerate citizens at a far lower rate than most developed countries: 48 per 100,000 people compared with 148 in Britain and 698 in America. This approach seems to work. Rates of recidivism for all ages are relatively low.

The system places huge emphasis on confessions. Admitting guilt is considered the first step towards rehabilitation. It is also, however, the “king of evidence” in cases too serious to let the suspect walk free. Last year confessions underpinned 89% of criminal prosecutions in Japan. And almost without exception, those who confess are found guilty. The overall conviction rate is a staggering 99.8%.

The trouble is, not all confessions are true. Some suspects will falsely admit guilt just to end a stressful interrogation, and interrogations in Japan can be very stressful. Police and prosecutors may hold ordinary criminal suspects for up to 23 days without charge—longer than most other rich countries allow even terrorist suspects to be detained. Access to defence lawyers during this period is limited. In theory, suspects have the right to remain silent; but in practice prosecutors portray silence as evidence of guilt.

Prosecutors put pressure on the police to extract confessions, and 23 days is plenty of time to extract one. Interrogators sometimes ram tables into a suspect, stamp on his feet or shout in his ears. Interviews can last for eight hours or more. Suspects are deprived of sleep and forced into physically awkward positions. Few people can withstand such treatment. “Not being able to sleep was the hardest for me,” says Kazuo Ishikawa, who held out for 30 days before signing a confession he couldn’t read (he was illiterate at the time) to a murder he says he didn’t commit. He spent 32 years in prison and is still fighting to be exonerated.

Sometimes police methods are strangely ritualistic. In 2003 in a small town in southern Japan 13 elderly men and women were falsely accused of electoral fraud. Police forced one man to trample on the written names of his family—just as early Christians in Japan were forced to trample on images of the Madonna.

Growing numbers of false confessions have come to light. Iwao Hakamada, for example, served 46 years on death row—probably longer than anyone else alive—before his release in March 2014. The judge who freed him found that police and prosecutors had fabricated evidence in his original trial for murder. He has also said he was interrogated for 11 hours a day for 23 days, beaten with nightsticks and prodded with pins when he fell asleep.

If in doubt, make it up

Keiko Aoki spent 20 years in prison after she confessed to having burned her 11-year-old daughter to death. In fact, her daughter died in a fire that started from leaking petrol in the family garage. But so harsh was Mrs Aoki’s questioning that she admitted to murder after just a day. She was released in October.

The scale of wrongful convictions is hard to gauge. One defence lawyer guesses that 1,500 people, or a tenth of the total sent to jail each year, are wrongfully convicted. One reason why past miscarriages of justice are coming to light is that DNA-matching techniques have improved. Defence lawyers and activists are calling for more cases to be reopened. Over a dozen are being investigated by teams of lawyers and supporters of those convicted.

A prominent case is that of Michitoshi Kuma, who was hanged for murder in 2008. A forensic expert, Katsuya Honda of Tsukuba University, who has helped secure recent exonerations, believes old and faulty DNA evidence was used to convict Kuma and that he was innocent. More than half of the 128 inmates on Japan’s death row (see article) are seeking a retrial.

The activists liken their push to one in America in the early 1990s that overturned many convictions, including of some prisoners who had been sentenced to die. In particular, they want to reform the rules that govern interrogations.

Prosecutors everywhere like to win; and in Japan they have extra incentives. An official survey five years ago found that nearly a third of them believed that a not-guilty verdict would hurt their career. (It might; most prosecutors have never lost a case.) A quarter said superiors had told them to write confession statements that differed factually from what defendants had actually said. Yet there is little scrutiny of misconduct. Even a probe of the procedures that robbed Mr Hakamada, who is 79, of most of his life appears unlikely. Prosecutors have clout.

Recent governments have made a few stabs at judicial reform. Japan does not have juries—a panel of judges decides whether the accused is guilty. But since 2009 the government has allowed ordinary civilians to become lay judges in certain cases. To date, over 50,000 people have served in this role in trials for serious crimes, including murder. Yet the use of lay judges has done little to reduce the system’s overreliance on confessions, or to lower the conviction rate.

At the time of that reform, the justice ministry also said it wanted more suspects’ interviews to be filmed. The police seem to be inching towards that goal, especially in cases that come before lay judges. Yet few interrogations are recorded from start to finish, so officers can still bully suspects when the camera is not rolling. Nobody expects filming of all interviews to be mandated any time soon.