For the gadget obsessed – and that’s me – Tokyo is technology central. But for the gadget possessed – me again – Tokyo sucks. Our mobile phones don’t work there. BlackBerries lie back and whimper, and you can slaver all you like over the most desirable, ridiculously inexpensive electronics, but do so in the knowledge that the instructions come only in Japanese, and that there will inevitably be some cunning little tweak that will render a product unworkable back home.

There, done it. Got the carping over. Now let me declaim on the subject of Tokyo and its glorious fusion with technology. Take the Tokyo subway system. You can set your watch by its spotless trains, which glide efficiently into stations at intervals of a few minutes. Each gleaming carriage has a screen with constantly up-dated travel information – can you imagine that on London Underground? And, rather endearingly, each rail station has a signature tune, which plays as the train arrives.

My first encounter with Japanese technology took me aback. The loo seat in the hotel bathroom was hot. Japan is a service culture, and the Mandarin Oriental, where I stayed, is magnificent in every way, but, even so, prewarming was more service than I expected. In fact, most Japanese loos come with multi-functional gadgets attached. The many buttons promised front or rear bottom spraying, oscillation (which seemed a wash too far), extra deodorising and seat heat control. Intrigued by a button showing musical notes, I pressed it, expecting Radio Tokyo, but only got a flushing noise. Apparently it’s an embarrassment-saving device. It made me smile every time I pressed it. I must have damn near worn that button out.

Tokyo is a vast city of many different ku (districts). Akihabara is, as the Japanese Tourist Board says, “No 1 electric city” and Yodobashi is its central shrine. It has the largest selection of consumer electronics in Japan. There are more than 600,000 items ranged over 11 floors. And, bliss, there are even three aisles worth of “shower toilets” with stern notices (aimed, I was told, at invading hordes of Koreans who are apparently their greatest fans) saying something along the lines of “all pedestals are different – don’t expect this kit to fit back home”. But they buy them anyway. After an hour of slack-jawed amazement, I had to be pulled from the shop by a determined translator so seduced was I by hair-dryer-type machines for drying knee-high boots, silent guitars, watch-sized TVs and battery-operated eyelash curlers.

What did I make of it? All of the colours and all of the sizes is the phrase that best describes Japanese technology. They take a basic bit of kit – let’s say a mobile phone – and then explode it into a multitude of forms. It is the ultimate niche market place.

Nowhere was this better illustrated than Yodobashi’s ground floor, home to a zillion mobiles. Ones that played TV, twisting ones, sleek ones and, hot, hot, hot ones you can match to one of 20 colours in the Pantone colour match system. At last, the phone to match the frock and the hand-bag and the shoes. And if you want the next trend here, think customising. Pimp my mobile, pimp my laptop, darling.

But there’s a darker side to technology in the city. Otaku is a derogatory word, with no exact translation, but nerds or trekkies is close. It describes obsessive loners, technofetishists who immerse themselves in manga(comics) or anime (cartoon films). They are to be found in the media cafés. The one I saw was faintly creepy, a subterranean world of individual cubicles, each with bed, computer and screen. With showers available and 24-hour access to vending-machine pot noodles, why go home? Indeed, many otaku stay for days or weeks. Three months was the record at the Popeye media café I visited.

Isolation is desired by many Japanese. Combine it with cheapness and you have the runaway success that are the famous capsule hotels. Tinned youth hostel best describes them, where you each have your own tin, complete with TV and coin-operated DVD player – and all for 3,000 yen (about £13) a night. Double-decker tin stacking ensures that 30 sleep in one room. The Capsule Inn was surprisingly comfortable, although getting out of my tin did require roping and a safety net and I emerged with several trophy bruises.

There are two aspects to the Japanese way with technology. Fusion is one, where computing gets mixed with physics or material science to create fabulous hybrid ventures such as bullet trains. The other is to play the long game. We pick up new toys and drop them. The Japanese go on honing and refining, investing, developing and exploiting until the technology is ubiquitous and works every time.

So-called ubiquitous networks are already being trialled in the posh shopping district of Ginza. Basically, your mobile device will be able to interrogate objects as you roam, which, thanks to their embedded technology, will momentarily become your computer. Miu-miu will know you are coming and call you, guiding you to its hallowed portals with GPS. It's a whole new world.

Such 2010 technology (and the Japanese are ten years ahead of us) was on display at Panasonic’s future lab in Koto-ku. The Japanese guide spoke English with an impeccable Scouse accent. When she stroked her hand in the air, a giant screen appeared on a wall. It did it all. Web, communications, checked your energy use, interrogated your washing machine, downloaded your music files to the car. It was a totally believable future – and the Japanese Government believes so, too. Its eJapan strategy has been and gone. They’re now on to a u-Japan strategy, as in u for ubiquitous.

The future is less certain for Wakamaru, the alarmingly yellow household robot created by Mitsubishi that I saw, available for 1.5 million yen (about £6,200). For me it had a touch of self-cleaning clothes and electric cars about it. So forget home robots, invest in ubiquitous networks.

Meanwhile, I have turned an important corner in my life thanks to my visit to Tokyo. Heated loo seats. They’re the future.

Need to know

Vivienne Parry travelled with British Airways Holidays (0870 2421276, www.ba.com/holidays), which offers five nights’ room only at the Mandarin Oriental, Tokyo, from £1,476pp, including flights.

Further information: Japan National Tourist Organisation (020-7734 9638, www.seejapan.co.uk, 0207-734 9638).

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