A few weeks later, engineers called and, after opening the box of cables in front of the house, found a strange thing: branching from Mr Ogata's line, an unknown extension led down the road. They traced the cable to a locked room in an apartment building 200 yards away. What Mr Ogata found in that room does a lot to explain the tumult this week in the Japanese parliament.
Yesterday afternoon, after days of acrimony and delaying tactics, the upper house of the Diet passed a Bill authorising police investigators, under certain circumstances, to tap the phones of criminal suspects.
In essence, the measure has much in common with legislation long in use in Europe and the United States - it can only be used with the permission of a court, and only on suspicion of serious crimes such as gun-running, drug-smuggling and murder.
It was eventually passed by 142 votes to 99, after a 21-hour session in which opponents filibustered and scuffled, and resorted to the "ox walk", shuffling towards the ballot box a few inches an hour to delay the vote.
The opposition MPs tabled votes of no confidence in the Prime Minister, and three parliamentary officers. Prominent among them was Mr Ogata.
Today, Mr Ogata is a member of the upper house representing the Japanese Communist Party (JCP). At the time of his phone trouble in 1986, he was the head of its international division. His phone was indeed being tapped, although at that time such activity was illegal.
Most serious of all, it emerged after months of cover-ups and obfuscation that those listening into Mr Ogata's conversations were officers of the local prefectural police.
Despite identifying the guilty officers, the Tokyo Prosecutor's Office declined to bring charges, on the grounds that "it would not be appropriate to question their individual criminal responsibility."
No one has been brought to justice for the crime, and no apology has been made. Even under the new law, spying on elected politicians would be illegal, but for many Japanese, particularly those on the left, the police are simply not to be trusted.
"If the police acted in such a way when wire-tapping was illegal," said the JCP chairman, Tetsuzo Fuwa, "they will certainly abuse their rights and authority if wire-tapping is made legal." As the left-leaning Asahi newspaper said in a leader yesterday, "We cannot but feel the sense of danger that people's freedom and privacy are being violated."
For all its economic hardships, Japan still has one of the lowest crime rates of any developed country. In Tokyo the most visible work done by police is directing lost pedestrians and helping drunks on to their trains home. But older Japanese remember a less benevolent side of their law enforcers, particularly the feared Kempeitai, or military police, who hunted down opponents of the government before and during the Second World War.
These days the police already enjoy tremendous power compared with a relatively weak and passive judiciary, effectively acting as judge and jury, as well as investigators.
Of criminal defendants charged and prosecuted, fewer than 1 per cent are acquitted. If judges are so unwilling to doubt the evidence of police and prosecutors, are they likely to take a discriminating attitude in their attitude to wire-tapping requests? "In foreign countries which already allow wire-tapping legally, there have been many problems," said Kazuo Shii, head of the JCP's secretariat. "It is very dangerous to give such a weapon to the Japanese police, who have such an abnormal character."Reuse content