Mr Nishiyama believes he is due an apology, but there is a larger issue at stake, he says.

'The Japanese government has lied and hidden the truth and it continues to do so,' he said. 'That is why I have filed my lawsuit. It's not important to clear my name. What is important is that people should know the government is acting in a way that threatens the fundamentals of our society, and the only way to fight that is through the courts.'

So far, his legal battle has had little success. On March 27, the Tokyo District Court rejected his demand for 33 million yen (HK$2 million) in compensation and an apology from the government on the grounds that an illegal conviction ended his career. The judge ruled that the 20- year statute of limitations on the case had expired.

Undeterred, Mr Nishiyama filed an appeal against the ruling on April 9. And although he is taking on the might of the government, Mr Nishiyama is forthright in his belief that now is the time for the Japanese public to hear his tale.

Mr Nishiyama was a highly regarded reporter with the Mainichi, covering politics. In April 1972, he reported that the Japanese government had the previous year signed a secret agreement with Washington and illegally paid US$4 million to cover the cost of returning areas used by the US military to farmland. The bilateral agreement shown to the public, however, showed that Washington would foot the bill.

A story under his byline appeared, but as he was the only journalist covering the issue - in itself a sorry state of affairs, he believes - he knew the government would find it easy to dismiss the reports and pressure him personally. The following month, he gave photocopies of the secret documents he had obtained to politicians of the opposition Socialist Party, who produced them in the Diet.

'They had approached me several times in the past and I had refused to give them information, but I finally decided that if I couldn't disclose what I knew then I was not doing my job as a journalist,' he said, defending his actions from the suggestion that they were politically motivated rather than to enable the public to form an opinion. 'It was a difficult decision to make and I'm not particularly proud of it.'

But it was Mr Nishiyama who became the target of attacks from the judiciary and the tabloid media - who were apparently more interested in how he had got hold of classified information from within the Foreign Ministry than in its content.

His source had been a ministry clerk, Kikuko Hasumi, with whom he had been conducting an extramarital affair and who had handed him the documents. As interest in the case snowballed,

Mrs Hasumi turned herself in to prosecutors and claimed that Mr Nishiyama had forced her to provide the documents by taking advantage of their relationship.

Mrs Hasumi was charged with violating the National Public Services Law, which bans civil servants from revealing state secrets, and given a suspended prison sentence. After a series of court cases and appeals, the guilty ruling against Mr Nishiyama was finally confirmed in 1978 by Japan's Supreme Court, which agreed that he had urged a government employee to provide him with secret documents. Once again, there was no consideration of what the documents had contained. He received a suspended prison term. He had already resigned from Mainichi four years earlier and he returned to Fukuoka.

The passing years have given his anger and resentment time to fester. 'Two witnesses in my first trial testified 18 times, all of which was perjury to avoid the illegality of the secret pact coming out.'

It was not until 1998 that the first firm evidence to support Mr Nishiyama's claims came out. In that year, a professor at the University of the Ryukus, Masaaki Gabe, found in the US National Archives the first document pointing to a secret agreement between the finance ministers of Japan and the US concerning Tokyo's provision of US$4 million for the return of Okinawa. In 2000, another declassified document backed up this discovery, as did a third set of paperwork on the same subject uncovered in 2002.

Most damaging for the government were the comments made by Bunroku Yoshino in 2006, during Mr Nishiyama's initial compensation suit. Speaking with the Asahi newspaper, the former head of the American Bureau at the Foreign Ministry said previous administrations had asked him to support the government's line or remain silent but that there had indeed been a secret deal.

Even armed with this admission, the Tokyo District Court dismissed Mr Nishiyama's suit - although the media that he criticises for failing to follow up on the discovery of the US documents had finally caught on to the story. Five days after the case was dismissed, an editorial in The Japan Times said the ruling 'defies common sense because of the

gap between the ruling and the known facts'.

'In Tuesday's ruling, the court said Mr Nishiyama's case could not proceed because the 20-year filing period had passed,' it pointed out. 'Using this technicality, the court avoided delving into the case itself.

'Because almost 36 years have passed since the signing of the reversion agreement, there should be no obstacle to the government's owning up to the existence of the secret pact,' the newspaper added. 'Its continued refusal to do so only deepens distrust of the government.'

Mr Nishiyama shakes his head, pointing out that officially Japan paid about US$320 million for the return of Okinawa, but in the form of a lump sum with no specific breakdowns or details of what was covered by the secret pacts. In fact, he claims, the genuine figure was close to double that amount, about US$600 million, which is the amount the US had demanded from the outset of the negotiations.

'Effectively,' he says, 'this was war reparations.'

The other positive side effect for Washington was that it enabled the US to continue to station troops on Okinawa, for which Japan continues to pay vast sums each year as part of the bilateral security arrangement between the two allies.

While most of his scorn is directed at the government for failing to come clean when all the evidence points to successive administrations pulling the wool over the public's eyes and instead encouraging the finger-wagging to be pointed in the direction of a journalist who merely did his job

too well, Mr Nishiyama is also

asking some questions about others in his profession.

'Bureaucrats provide information that is beneficial to them and hide that which is not convenient,' he said. 'You can never expect whistle-blowers to come out from among the bureaucrats. The bureaucracy has an iron curtain.

'When one tries to get secret information, it always involves some kind of irregularity,' he said. 'In my case, the government and the media attacked me for my irregular method of getting the data - even though it would have been impossible otherwise to get the information.

'It is very important that the media pursue the truth and tell the Japanese public,' he said. 'When the media stopped pursuing the government's crimes, they were committing journalistic suicide.'

Perhaps the final irony of the legal case is that in 1974 - as Mr Nishiyama was fighting his corner through the Japanese courts - prime minister Eisaku Sato was awarded the Nobel Peace Prize, primarily for overseeing the peaceful transition of Okinawa back to Japanese sovereignty.

In his Nobel lecture on December 11, 1974, Mr Sato said:

'It cannot be said that these negotiations were easy. However, the US, as a friendly country, lent a willing ear to the Japanese request. Finally, the great achievement of realising the return of territory through diplomatic negotiations, an event rarely witnessed in world history, was achieved.

'Okinawa is a shining example of a peaceful modification of the status quo and that it also contributed to the relaxation of tension in Asia, and to stability in the Western Pacific region,' he added. 'As for Japan, the return of Okinawa has served as a major factor in fostering political stability.'

Had the Nobel Foundation committee that chose that year's winner known of the dubious transactions that helped smooth that transfer, and coincidentally helped cement the Liberal Democratic Party's control of political power, they may have been more reluctant to honour Mr Sato.