Every day for the past 30 years, condemned murderer Sadamichi Hirasawa has awakened to the fact that, legally, he has an appointment with the hangman. Since he is now 88 and has been in prison so long, his execution is highly unlikely. But the threat remains unabated. And to many thoughtful Japanese it shows some of the less attractive aspects of the country's legal system.

On the one hand, Japanese police, helped by high public respect for the law, have earned an enviable international reputation for their success in curbing serious crime.

And, when an arrest is madE, there is the remarkable fact that over 99 percent of the cases lead to conviction.

But, as a result, there is a tendency to assume the police are incapable of making a mistake, that no arrest is made unless guilt is absolutely clear.

This attitude manifests itself most clearly in news media treatment of criminal cases, in which the reporting is not hindered by any considerations of libel, of due process, or of a case being sub judice.

Britons recently were worried about press reporting of the "Yorkshire Ripper" case, particularly an overexuberant assumption of the arrested man's guilt.

Japanese newspapers, however, regularly carry the confessions of criminals long before they are presented in court.

The assumption of "guilty until proved innocent" is particularly apparent when the arrested person has a previous criminal record, or has some slightly dubious occupation like being a bar hostess or Turkish bath operator.

Anyone subsequently found innocent by the court has very little redress against this excessive reporting.

The high conviction rate is the result of the traditional thoroughness of Japanese police, who employ one of the world's most scientifically advanced criminal detection methods and who are supported by a complex array of laws as well as social mores that give the prosecutor every advantage.

There is no trial by jury, and the assessment of the case is left entirely in the hands of a panel of judges.

Most Japanese have never seen the need for a jury. Partly this stems from their additional unquestioning attitude to the superior, professional qualifications of those set over them.

Juries were introduced experimentally before World War II, but Justice Ministry officials say the system did not work well and was dropped after a few years. The basic problem was that being a homogeneous people, Japanese didn't like to judge others in the cut-and-dried way required in a courtroom. Many people were also concerned that they might be criticized by friends and neighbors for their decision -- and Japanese don't like to be put in the position of sticking out in society like a loose nail in a floorboard.

Another differences from Western criminal justice is the great emphasis placed on written evidence, whether that of witnesses or confessions of the accused.

In fact, confession has long been regarded as the king of evidence, acceptable in court even if subsequently revoked by the defendant.

Undoubtedly in the past the police sometimes used torture. These days the pressures of confinement and prolonged interrogation help produce results 86 percent of the time.

A suspect brought before the prosecutor has to decide whether to proceed to an indictment, and there is little prospect for the ordinary man having a lawyer present to protect his rights in the prolonged questioning sessions.

A refusal to answer questions, in fact, can be regarded as demonstrating lack of remorse -- a vital factor with judges in deciding sentence.

Criminal lawyer Tasaku Matsuo complains, for example, that many of his colleagues spend most of their time pleading for a reduced sentence rather than battling, Perry Mason style, to expose the prosecution's weaknesses for acquital.

All this is opposite to the case of Sadamichi Hirasawa. On Jan. 26, 1948, a self-important little man in a business suit called on the manager of a Tokyo bank, claiming to be a sanitation official from the Tokyo health department.

He had come to dispense "anti-dysentery powder," which all 16 bank employees gulped down with tea. The powder was cyanide. Twelve died; the other four survived.

The poisoner fled after snatching the equivalent of $184.

Months later, police arrested Hirawasa, an unsuccessful artist with no means of support but carrying the equivalent of $134 -- a large sum at the time.

He resembled a composite picture drawn by the survivors, but none of them later picked him out at a police lineup.However, after attempting suicide three times, Hirasawa made a full confession. This he later withdrew, claiming it had been obtained by torture.

The court accepted the written document, even though the accused presented a fairly convincing alibi for the day of the crime, and police did not establish how he got the poison.

He was sentenced to death in June 1950, with the Supreme Court rejecting his final appeal in 1955. Yet Hirasawa is still alive, though executions are still carried out in Japan, and a majority of Japanese approve capital punishment.

Sixteen requests for a retrial and three petitions for an amnesty have been rejected over the years. The Central Rehabilitation and Protection Council, in rejecting the latest amnesty petition last December, said, "It cannot be doubted that Hirasawa was the perpetrator of this cruel crime. . . . Even now he continues to protest his innocence and shows no signs of remorse."

A growing number of Japanese now believe this is because he really is innocent, and they believe the fact he has not been hanged is a tacit admission of this by the authorities.

Hirasawa, it seems, will eventually die in prison. But last January he adopted the eldest son of the man who has long led the campaign to free him. This ploy will allow Takehiko Morikawa, 22, to continue the campaign after the death of the childless condemned man.

In this, encouragement is provided by the case of the late Shigeko Fuji. She died in jail last year while serving a murder sentence. Her family subsequently obtain ed an acquittal on the grounds of forced confession.