The police station at Oimachi has seen better days. In the small interview room, on the third floor, the aging linoleum is scuffed, the bare walls seemingly unpainted during Japan’s lost decade.

Officers wandered about the squad room beyond — chattering to their radios, pulling forms from desk drawers — pausing only to acknowledge the 5 p.m. anthem piped over the loudspeaker system. It had been barely 12 hours, but it felt a long way from the pristine arrivals hall at Haneda Airport.

A detective came in and sat down. The two-man patrol explained the detention. This gaijin (foreigner) had committed an offense: riding a commuter train without a passport.

The officers were apologetic but resolute: Foreigners in Japan must carry an alien card or passport at all times. Leaving a passport securely in a hotel room was no defense. At the time, it was no laughing matter. “If you are arrested in Japan, even for a minor offense, you may be held in detention without bail for several months or more during the investigation and legal proceedings,” according to the U.S. Bureau of Consular Affairs.

At Oimachi, the detective smiled when I told him that this gaijin intended to leave the country within a few days of arriving. This potential flight from justice prompted a flurry of hurried conversations. Other officers wandered in, all with pistols prominently on their sides.

“You must bring us your passport,” they said. They were nonplussed by the response: “Of course, but it is in Yokohama. And I don’t know where you are holding me.”

Although there have been no major terrorist incidents in Japan since 1995, the security forces remain on a high state of alert. A foreigner, changing trains from the Negishi to the Rinkai Line, was enough to arouse suspicions. Two officers on patrol, sporting gray raincoats over their uniforms, were polite. They flashed gold badges and said, “Please follow us.”

In previous encounters, policemen have proved less emollient. Almost 30 years ago, at the time of my last police detention, politeness was not part of the repertoire — especially when officers from the Royal Ulster Constabulary (RUC) were involved. Back then, no one opened the police car door. No one bowed. Instead, my arms we pinned behind me. I was frogmarched into the compound shared by the RUC and British troops in Suffolk, west Belfast.

It was the height of “The Troubles,” the sectarian strife that plagued Northern Ireland for generations. This time the offense was not a missing passport; it was photography. But the perpetrator’s miscalculation was the same: naivety, aggravated by not following the rules.

In mid-1980s Belfast, anyone caught photographing security facilities risked prosecution under the Prevention of Terrorism Act. The crime: gathering information that might be useful to a terrorist.

As a newly arrived volunteer on a peace-line project — the programs that aimed to bring Catholic and Protestant communities together — the compound was begging to be photographed. The high brick walls were stained in bright colors, the result of paint bombs thrown by local gangs. Wrecked cars were lined up by the main gates, towed there following traffic accidents to prevent them being used as barricades in street protests. Cameras on high masts surveyed the nearby “peace fence,” the 10-meter-high barrier that separated Catholic and Protestant residents.

Having snapped a few pictures, I received an involuntary tour of the compound. Almost 8,000 km from Oimachi, it was a far cry from the seemingly relaxed and endless bureaucracy of a Japanese police station.

This was a Belfast fortress. Beyond the outer gates, the walkway weaved through a concentric maze of blast walls, designed to contain mortars or bombs. In Japan, the detainee was allowed to send emails and texts. In Belfast, decades earlier, Apple and Blackberry were still types of fruit. For anyone questioned by the RUC in the 1980s, broadband penetration probably meant something quite different.

In Oimachi, there was clear 3G connectivity. In west Belfast, a cell phone was the one call you were allowed from your cell.

Unlike the Japanese police, the RUC was not inclined to deference. Shoe laces, belts, wallets and other personal effects were removed. In an interview room, a heavyset sergeant made an odd knocking sound. He was thumping his bulletproof vest. “The provos (Provisional IRA) are trying to kill me. The last thing I need is a Brit on my doorstep,” he growled. “If I know you’re here, they know you’re here. And if they lift you, I can’t do anything about it.”

I was released, eventually, without charge and without my camera.

Had I been convicted under the U.K.’s Prevention of Terrorism Act, it is doubtful I would have been admitted to Japan in the first place — let alone for the quarterly trips to meet Japanese business clients.

But like the RUC a generation earlier, the Oimachi constabulary seemed genuinely surprised to find a Brit in their midst. On the ride to the police station, the driver asked his colleagues whether it was an American in the back. “No, English,” he was told. The driver nodded and intoned something hard to decipher.

At the station, a police interpreter was found. He informed me that a valid driver’s license might be sufficient ID for traveling around the U.S. or Europe, but not in the world’s third-largest economy. Even so, one of the officers decided to make a copy of the licence. Instead of simply photocopying it, he wrote down every word on a plain sheet of paper, including the code: AM/A/B1/B/C1/D1/BE/C1E/D1E/f/k/l/n/p/q. This code does not represent personal identification, but types of vehicle. As a result, a few Tokyo policemen might now be able to recite every vehicle code on a British driving licence.

Earlier that day, I had already encountered Japan’s increasing diligence over counterfeit documents. At Haneda’s immigration counter, the desk clerk looked up from his computer and inquired whether my passport had ever been reported lost or stolen. Told that it had been — earlier this year in Paris — there was a flurry of phone calls. There was a groan from the other passengers waiting in the queue. An officer appeared and escorted me to a waiting room. After various checks and a short delay, the replacement passport was duly stamped and returned with a two-handed bow.

Trying to explain this immigration inquiry to the Oimachi police might, I feared, have prompted further delays, police questioning and still more form-filling. Instead, this gaijin hoped to become just another statistic among the dwindling number of foreign visitors cleared of non-traffic penal offenses.

The escape route was a simple one. The trick was to become a bureaucratic headache — an irritant — rather than a danger to society. I didn’t know where I was or what I had done wrong. The officers were probably nearing the end of their shift. It was getting dark. They wanted the Brit to go home.

Last century, the same tactic also worked in Belfast. I was simply in the way, rather than obstructing justice. It was easier to release the irritant without charge.

Unlike in Northern Ireland, Japan’s exceedingly polite officers waved me off with a smile. In Belfast, the RUC had issued a veiled warning: Watch your back. In a Tokyo suburb, the warning was less menacing: Don’t come back without your passport.

Tim Burt, a former Financial Times journalist, is managing partner of StockWell Communications. Foreign Agenda offers a forum for opinion on Thursdays. Send comments to community@japantimes.co.jp.