Despite official data showing public support for capital punishment running at around 80 percent, few Japanese are willing to openly defend the death penalty.

One of them is a specialist in criminal policy, Kazuhiko Tokoro, professor emeritus at Rikkyo (St. Paul's) University in Tokyo.

However, it's a position he takes with reluctance, as when he was a panelist on the Nihon Gakujutsu Kaigi (Science Council of Japan), often dubbed "the Diet of Scholars," at its 1997 symposium when for the first time ever it discussed this issue.

In a recent interview, Tokoro explained his views to The Japan Times.

Why does Japan have the death penalty?

Basically, one of the roles of punishments in society is to help deter people from committing crimes by letting them know about the penalties they face.

If asked the significance of the death penalty, I would answer that it makes clear to people the gravity of the worst, cruelest crimes, which are penalized with the heaviest punishment.

The existence of the penalty plays a role in nurturing and strengthening basic morals in people's mind, which consequently prevents people committing more serious and cruel crimes in the future.

How can it be legally justified to kill people even as a form of a punishment?

It can only be so when all the due processes have been gone through. This means that we have to have fair trials and make full use of human wisdom to try to avoid misjudgments.

Article 31 of the Constitution says: "No person shall be deprived of life or liberty, nor shall any other criminal penalty be imposed, except according to procedure established by law."

Although the Supreme Court in 1948 famously declared the death penalty to be constitutional, it also said: "A human life is heavier than the globe." I believe this to be so.

Despite that, we have the death penalty because I think we cannot avoid having the punishment to save human lives which are also heavier than the globe. If having the death penalty helps protect the human rights of potential victims, I think we are allowed to retain it.

Some cite the sentiments of victims or the bereaved in support of the death penalty, but I think the issue goes far beyond people's sentiment, and is about human life. Nobody is allowed to kill anybody out of hatred.

Some people doubt the death penalty's role as a deterrent, and data from the Death Penalty Information Center in the United States, for example, shows the murder rate is higher in states that have it than in ones that don't. What do you say to this?

It is far too simplistic to determine from such figures that capital punishment plays no role in helping to decrease crime, because lots of other factors in society can influence the murder rate. In the realm of statistics, to clarify the effects of the death-penalty system on crime rates requires very complicated and detailed calculations. That is why it is very difficult to scientifically prove the relationship between the death penalty and crimes.

However, it is true that recently the death penalty's role as a deterrent -- by making people compare the benefits to them of committing murder with the loss they face from the death penalty -- has not been greatly emphasized.

What I said is slightly different from this idea. I focus more on the death penalty's role in nurturing people's conscience by telling them the gravity of such crimes. This is called an "active" prevention effect, which makes people refrain from committing cruel crimes based on their developed conscience. It would take time to recognize this effect, which is why I say it would be difficult to demonstrate the evidence.

Because the death penalty is carried out in such secrecy in Japan, how can people learn the gravity of crimes that must be paid for with their lives?

It is true that the criminals are secretly executed. Also there is often a long time before the execution takes place, meaning that the original case has become buried in people's memory. But still, when death-penalty sentences are handed down, it registers in people's minds, so they learn the gravity of the crimes.

Do you believe the heaviest sentence should be death?

I believe the degree of the punishment should reflect the gravity of the crimes proven to have been committed. Japan has the life-imprisonment penalty, but it has a system of parole. Life imprisonment without parole could replace the death penalty in terms of the heaviness of the punishment. But to be honest, I do not know if this is realistic. I really don't know.

How do you feel about the possibility of wrongful conviction in capital cases?

Wrongful conviction is a very serious problem whether or not the death penalty is involved. It is true that the problem is especially serious in capital cases, because it is irreparable. I know that opponents of capital punishment argue that it should be abolished because of the possibility of wrongful convictions. But this argument is something that eventually leads to a questioning of the whole judicial system.

If the possibility of wrongful conviction were not zero, but was very small -- and if it were not the result of partiality -- then we should tolerate the system . . . as long as we retain the death penalty.