One day, in just a few years' time, people all over Japan will begin to find unexpected official letters in their mailboxes. Perhaps anxious that they have done something wrong, or failed to make a payment, it will be with considerable tredipation that most seek out the contents.

But as they will then discover, they needn't have worried about fines or debts -- though the summons in the envelope may be just as troubling to many.

That is because these letters will be from their local District Court -- to inform them that they may be required to serve as a saibanin (lay judge) within the next year.

Scheduled to start in May 2009, what is being termed the saibanin system marks a major societal watershed, as it will be the first time in postwar history for the general public to participate in the hermetically closed operation of Japan's criminal justice system.

At the outset, the cases that saibanin will be asked to judge will be limited to those involving serious charges only, such as murder, rape and arson. Consequently, citizen judges may find themselves not just fining or jailing those they convict, but possibly sentencing them to hang.

"The reason why serious criminal cases were chosen was because there is great public concern about such issues, and such crimes have a great social impact," explained Ryuji Hatano, an official in the Justice Ministry's Criminal Bureau.

"But that does not mean that we will not consider broadening the range of cases in the future."

So what kind of people are likely to receive one of these dreaded letters?

Potential saibanin will first be randomly chosen every year from the voter rolls for parliamentary elections. Consequently, potential saibanin will be Japanese nationals aged 20 or over, meaning that not only resident foreigners but even resident Japanese of Korean origin will be excluded.

After this first-stage random selection, a second "lottery" will determine who is told they are on the waiting list. After that, another random selection will finally lead to the delivery of those official letters summoning citizens required to appear at the court. There, a District Court judge will determine who among the candidates is eligible to serve as a saibanin in whatever case the selection is being made for.

Voters excluded from service will include those who are Diet members, ministers, lawyers, prosecutors, professors of law, members of the Self-Defense Forces and those who have been sentenced to imprisonment.

Relatives of the accused or alleged victims will also be barred from serving as saibanin -- though, oddly, friends and ex-fiances will not.

"It is, however, highly unlikely that [friends or ex-fiances] would be chosen," Hatano said. "Because the prosecutors or lawyers can use their special rights to disbar up to four people each from the list of saibanin candidates for a case without giving a reason."

Using that prerogative, if by chance all the saibanin for a trial ended up being male or female -- and if the defense lawyers or prosectors were not happy about that -- they could exclude up to four individuals to make way for replacements who balanced out the sexes.

Once chosen, saibanin will generally not be able to decline to serve.

Certainly, work commitments or obligations will be no grounds for removal, as employers will not legally be able to prevent employees serving. However, anyone who is very ill or badly injured, over 70 years old or a student, will have that right.

After this lengthy process, then, for most trials, six people will have been selected to sit in judgment with three judges.

The Saibanin Law, however, does provide for certain cases to be heard by just one judge and four saibanin -- such as ones in which the facts are not in dispute and the defendant has pleaded guilty as charged.

Finally, whether with six or four saibanin, when the trial begins there is the problem for these citizens of how long the court proceedings will continue to disrupt their normal lives.

At present, Japan's trial system is infamous for being extremely long and drawn out -- and difficult for lay people to understand. In concert with the introduction of the saibanin system, though, revisions to the Criminal Procedure Law are intended to help speed things up.

Hatano estimated that although it may differ according to each case, a trial that once typically took two to three months may henceforth be conducted in two or three days.

Once all of the evidence has been presented and the defense and prosecution arguments have been heard, the saibanin and the judge or judges will jointly discuss the verdict.

Majority verdict

Although they will ideally seek consensus, if that is not possible to achieve, then a majority verdict will be sufficient to convict or acquit in most cases.

If, however, all three judges found a defendant not guilty, but all the saibanin voted to convict, then in order to prevent an innocent person being convicted, the defendant would be found not guilty.

Once a guilty verdict is arrived at, there comes the sentence -- which may include the death penalty, life imprisonment, imprisonment for a definite term and/or a fine. That, too, will be subject to agreement between the professional judge or judges and the saibanin.

After that, when the presiding judge has handed down the sentence, the citizens' saibanin job is done -- well, for five years at least. After that, they might just find another of those envelopes waiting in their mailbox again.

In the meantime, however, former saibanin would be well advised to remember that if they leak information about the discussion that went on behind closed doors between the saibanin and the judge or judges, it could be them in the dock next -- facing a fine of up to 500,000 yen or up to six months' penal servitude.