'I'm as sharp as a razor, but I can't hear a thing'

Richard Lloyd Parry discovers how it feels to be deaf and infirm in a suit that simulates the effects of advanced age

I'm walking very slowly down a little street in Tokyo, trying not to get run over by the push-chair, and discovering all the things I can't do any more. I can't walk very fast because my knees don't bend properly, and an impatient queue forms behind me as I negotiate the ramp up to the supermarket. I can't get the change out of my pocket, either, and when the girl at the till tells me the price I can't hear what she's saying. I'm hot and irritable and increasingly itchy. Just a minute, that's the last straw - I can't even pick my nose.

From the outside I look like a cross between a skateboard champion and one of Darth Vader's stormtroopers. Inside, I feel the opposite: slow, heavy-limbed and vulnerable. A couple of kids suddenly whiz across my narrowed vision, nearly knocking me over. Young punks!

In the past half hour I have come as close as you can to ageing 50 years. I am wearing something called the "Senior Simulator". It's described as a suit, but it's more like a collection of dastardly accessories, each designed to reproduce one of the effects of advanced old age. Plastic and Velcro splints stiffen your ankles, knees and elbows. The pockets of the jacket contain weights that drag down your shoulders and back. You wear plugs in your ears, and goggles that dim and narrow your vision. There are three sets of gloves - skin-tight latex, then thick cotton to dull the touch (hence the nose-picking problem), and elastic to arthriticise the fingers. The parts are purpose made by a surgical supplies company; an entire suit costs about pounds 2,000.

In Japanese, the suit is called "Taro Urashima", after a character from folklore, a fisherman who discovered a secret underwater kingdom where he spent years among the sea princesses and water spirits. When he left, he was given a mysterious box with the strict order never to open it. Inevitably, he disobeyed; suddenly, like Dorian Grey, Taro was transformed into an old man.

It's an uncomfortably appropriate parable. In Japan, people live longer than anywhere else in the world; yet Japan has one of the lowest birth rates. By some estimates, more than a quarter of the population will be over 60 by the year 2000. "That means there will be fewer people to look after the elderly, and fewer taxpayers to pay for the cost of their social security," says Shukichi Gonjo, who invented the Senior Simulator. "The government doesn't realise how serious it is, but it'll be a genuine crisis. In a few years, the pension system could collapse."

The Japanese who will retire in the next 10 years are a different breed from the present generation of elderly. The post-war boom broke up the traditional extended family, in which elderly parents would live with their sons and daughters-in-law as children moved away to the cities. The economic miracle had another effect: many workers, mostly men, were robbed of any sense of leisure time. Hours were long, holidays short, weekends typically spent sleeping, golfing (often with clients) and watching television. "You get these men who have devoted their lives to their company, who have no hobbies, no idea of how to enjoy themselves," says Mr Gonjo. "Their wives are lively, but they just lie down at home in front of the TV. In Japanese, they're called 'wet leaves'. When leaves are wet, they just lie there, even when you brush them."

Mr Gonjo's organisation is called the Wonderful Ageing Club (WAC), and one of its functions is to blow-dry the wet leaves. He organises outings, meetings and voluntary activities, the most popular job of which is acting as "instructor" on the simulator. Armed with the suits, gangs of WAC members pay visits to schools, companies and government offices. They are hilarious occasions, as proud branch managers are reduced to shambling octogenarians in front of their giggling employees. "But people are very moved, too," says Mr Gonjo, "especially those who have elderly parents. We get letters from people saying that they feel guilty now about being so intolerant, that for the first time they understand what it's like to be old."

Taking off the suit is a relief: I have been a horrible old man. Surprisingly, it's not the deafness or the immobility that are most alarming but the isolation. I ask Mr Gonjo a question and the people around us smile and wince because I'm shouting, unable to judge the volume of my own voice. After that I whisper, but they keep having to repeat the answers, so my colleagues ask the questions on my behalf. I may be a bit of a wreck, I want to say, but between the ears I'm still as sharp as a razor. Someone else, though, is conducting my interview, and writing in my notebook. I sit at the side, ignored.