'Sa zi mian? What noodles d'you want?' Xie Laoban gave me his usual surly look as he glanced up from the conversation he was having with one of his regulars.

'Two liang of sea-flavour noodles, one liang of Dan Dan noodles,' I replied, dumping my schoolbag on the ground and perching on an unsteady stool, just inches from the stream of passing bicycles. There was no need to look at the blackboard, chalked up with the names of a dozen or so noodle dishes, because I knew it by heart, having eaten at Xie Laoban's almost every day since I had arrived in Chengdu. Xie Laoban yelled my order out to his staff of three or four young blokes, who were scurrying around inside the noodle shop behind the coal-burning stove. A glass cabinet held bowls of seasonings: darkly fragrant chilli oil, ground roasted Sichuan pepper, sliced green onions, soy sauce and vinegar, salt and pepper. Nearby, potfuls of stocks and stews simmered away on an electric cooker, and skeins of freshly made noodles lay snakily in deep trays of woven bamboo. At the front of the shop, in full view of the street, steam drifted up from two enormous wokfuls of boiling water.

Resuming his conversation, Xie Laoban slumped back in his bamboo chair, smoking a cigarette as he recounted some grimly amusing tale. There was always an embittered look about his face, an edge of hostility and suspicion, and if he smiled at his acquaintances, his smile was tinged with a sneer of sarcasm. In his forties, he had a face pitted with the legacy of acne, sun-darkened yet wan and drawn. He seemed world-weary and cynical, though my foreign student friends and I never knew why. He fascinated us, but while we speculated incessantly about his life, wondering where he lived and with whom, what he did in the evenings, and whether he had ever been happy, in the end it was hard to imagine Xie Laoban being anywhere else but in that bamboo chair in the backstreets around the university, taking orders for noodles and barking at his staff. The bolder among us -- Sasha and Pasha from Vladivostock, Parisian Davide -- greeted him heartily, trying to engage him in conversation or cracking jokes in a vain attempt to raise the glimmer of a smile. But he remained stony-faced and deadpan, simply asking, as he always did, 'Sa zi mian?'

I could see the young men assembling my lunch, trickling spices and oils into the tiny bowl for my Dan Dan noodles, sprinkling a little salt and pepper into the larger bowl for the sea-flavour noodles. The appropriate weight of noodles (one liang is about fifty grammes) were flung into the wok to cook, and before long steaming bowls were brought to my table. The sea-flavour noodles were, as always, richly comforting in their seafood broth, with a topping of stewed pork and bamboo shoots, mushrooms, dried shrimps and mussels. And the Dan Dan noodles -- well, they were undoubtedly the best in town, the best anyone had ever tasted. They looked quite plain: a small bowlful of noodles topped with a spoonful of dark, crisp minced beef. But as soon as you stirred them with your chopsticks, you awakened the flavours in the slick of spicy seasonings at the base of the bowl, and coated each strand of pasta in a mix of soy sauce, chilli oil, sesame paste and Sichuan pepper. The effect was electrifying. Within seconds, your mouth was on fire, your lips quivering under the onslaught of the pepper, and your whole body radiant with heat. (On a warm day, you might even break out into a sweat.)

Xie Laoban's Dan Dan noodles were a potent pick-me-up, a cure for hangover or heartache, and the perfect antidote to the grey humidity of the Chengdu climate. As students, we were slavishly addicted to them. Many, like me, ordered a gentler meal of soup noodles with fried egg and tomatoes or sea-flavour stew, with a small shot of fiery Dan Dan noodles as a chaser, while the fast-living, hard-drinking Russians and Poles invariably ordered a full three liang of 'dan danr'. We devoured them at one of the wobbly tables in the street, brushed by bicycles, assaulted by the honk of taxis and their sour aftermath of exhaust fumes. When we had finished, we asked Xie Laoban for the bill, and he would add up the paltry sums, take our crumpled notes, and rootle around in the little half-open wooden drawer for some change.

Dan Dan noodles are the archetypal Chengdu street snack. Their name comes from the bamboo shoulderpole that street vendors traditionally use to transport their wares: the verb 'dan' means to carry on a shoulderpole. Elderly residents of the city still remember the days when the cries of the noodle sellers -- 'Dan dan mian! Dan dan mian!' -- rang out in all the old lanes. The vendors would lay down their shoulderpoles wherever they found custom, and unpack their stoves, cooking pots, serving bowls, chopsticks and jars of seasonings. Servants would hear their call and rush out to the gateways of the old wooden houses to order noodles for their masters. Mah Jong players, clattering their tiles in a teahouse, would interrupt their game for a bowlful. Passers-by would slurp them in the street. The noodles were served in tiny bowls, a liang at a time, just enough to take the edge off your hunger, and so cheap that almost anyone could afford them.

The noodle sellers weren't the only traders on the move; they were part of a thriving and colourful street life for which Chengdu was renowned. At the end of the Qing Dynasty, in the early twentieth century, a guide to the city by Fu Chongju included descriptions and illustrations of some of its many street traders, including itinerant barbers and pedicurists, water-carriers and flower-sellers, menders of parasols and fans, vendors of chicken-feather dusters, knife sharpeners, and snack makers. The old city was a maze of alleys lined with timber-framed houses, their walls made of panels of woven bamboo that were packed with mud and straw, then whitewashed. Stone lions stood on pedestals at either side of imposing wooden gateways. There was a teahouse on almost every street, where waiters with kettles of boiling water scurried around, refilling china bowls of jasmine-scented tea. And amidst the cacophony of the markets and the bustling streets, no sound was more welcome than the cry of a snack-seller, advertising the arrival of some delicious xiao chi, or 'small eat'.

The late nineteenth and early twentieth centuries are remembered as the heyday of Chengdu snacks. Street vendors lived or died by the quality of their cooking, so the secrets of their methods were jealousy guarded. In an atmosphere of fevered competition, individual traders devised new recipes, some of which still bear their names. One man, Zhong Xiesen, invented the divine 'Zhong boiled dumpling' (zhong shui jiao), a tender pork-filled crescent bathed in spiced, sweetened soy sauce and chilli oil, and finished off with a smattering of garlic paste. Another, Lai Yuanxin, left to posterity his squidgy glutinous rice balls (lai tang yuan), stuffed with a paste of toasted black sesame seeds and sugar. A married couple who roamed the streets with their cooking equipment had a relationship so famously harmonious that their speciality -- slices of beef offal tossed with celery and roasted nuts in a fiery dressing of spiced broth, chilli oil and Sichuan pepper -- is still known as 'Man-and-wife lung slices' (fu qi fei pian). The more successful traders often went on to open their own restaurants, usually named after their most celebrated snack.

During the Cultural Revolution, any kind of private enterprise was banned. The teahouses of Chengdu were forced to close, and snack-sellers were banished from the streets. Yet soon after the end of China's 'Decade of Chaos', the old street-food culture heaved itself back into life. Its resurgence was partly a symptom of the 'smashing of the iron ricebowl' -- the post-Mao dismantling of the old socialist system that had guaranteed jobs and incomes for life. Middle-aged workers suddenly found themselves 'laid-off' on subsistence wages, and were forced to find other ways to make money. So some of them would fry up a basketful of ma hua (dough twists) in the mornings, or put together some zong zi (glutinous rice wrapped in bamboo leaves), which they took out into the streets to sell. And there were peasants making a bit on the side in the slack farming season.

The eyes of the older generation tended to mist over when they recalled the street food of their childhoods. One elderly man I met in a teahouse sat with me for an hour, writing out in meticulous detail a list of dozens of kinds of dumplings, categorised according to their cooking method and main ingredients. A portly and jovial chef in his fifties smiled wistfully as he reminisced: 'Oh, they were all out there on the streets, sold from the shoulderpole, Dan Dan noodles, "Flower" beancurd and toffee.' And he sang for me a long-remembered street vendor's chant: 'I got sweet ones, crispy ones, sugared dough twists!'

The old streets of the city were endlessly fascinating, and I spent much of my time exploring them. In shady corners, barbers hung mirrors on tree trunks or the walls of convenient buildings, and set up bamboo chairs for their clients, who lay back to be frothed and shaved with cut-throat razors in full view of the street. Knife sharpeners wandered past in dirty aprons, carrying their wooden stools and long, grey whetstones, ready to bring a keen edge to anyone's cleaver. There were mobile haberdasheries, carried on bicycles that were pegged all over with zips, buttons and reels of cotton. Some pedlars sold their own handiwork -- colanders woven from strands of bamboo, or black cotton shoes with padded white soles.

In the mid-nineties, Chengdu was still a labyrinth of lanes, some of them bordered by grey brick walls punctuated by wooden gateways, others lined with two-storied dwellings built of wood and bamboo. The grand old houses had been divided up into more humble living quarters, plastic signs had been hoisted up above the open shopfronts, and the stone lions had disappeared from their pedestals. But if you closed your eyes to these signs of change, you could imagine yourself walking through a more distant Chinese past.

In the alleys there were wine shops, with strong grain spirits sold from enormous clay vats. Some of the wine was steeped with medicinal wolfberries, some -- for the gentlemen, of course -- with assorted animal penises. Flute-sellers wandered among the crowds with bamboo pipes slung all over their bodies, playing a melody as they went. And it was hard to go more than a few yards without being tempted to eat. I might be waylaid by an old man selling sesame balls; distracted by someone selling glutinous rice dumplings wrapped in tangerine leaves from a steamer on the back of a bicycle; or arrested by the scent of eggy pancakes stuffed with jam, fresh from the griddle.

In March, when the spring winds whipped up, there was a kite vendor on every thoroughfare, displaying colourfully painted birds and insects made from bamboo and tissue-thin paper (the whole wide sky was full of them, too, like a swarm). When it rained, sellers of foldaway waterproofs appeared as if by magic; in the soupy summer heat, old men laid out rows of fans on the pavement. I even saw, once, a bicycle stacked with hundreds of tiny cages woven from thin strips of bamboo. Each one contained a live cricket, a potential pet; together, they hummed like a small orchestra.

The notes ding ding dang, ding ding dang, beaten out on two ends of a piece of metal, signified the arrival of the Ding Ding toffee man, selling his pale, malt-sugar sweetmeat, which melted stickily in your hand if you didn't eat it quickly. Best of all was the shouted 'Dou huar! Dou huar!' of the Flower beancurd vendor. I would rush to catch up with him, and he would put down his shoulderpole and the two red-and-black wooden barrels suspended from either end, and set about making me up a bowl of beancurd. It was still warm from the stove, as soft and tender as crème caramel, with a zesty topping of soy sauce, chilli oil, ground Sichuan pepper and morsels of preserved mustard tuber.

I never saw street vendors selling Dan Dan noodles. Like the famous Zhong dumplings and Mr Lai's glutinous riceballs, they had disappeared from their original habitat, and were served instead in specialist snack canteens, or as a kind of amuse-bouche in more glamorous restaurants. On the streets, they'd been replaced by newly fashionable titbits: Shanghai fried chicken, Xinjiang potatoes or barbecue skewers. Every few months a new street-eating craze arrived, and a rash of identical stalls would jostle for position with the dispensers of more established fare.

Although the name Dan Dan noodles refers only to the way in which the snack was sold from a shoulderpole, over time it has become associated with a particular recipe, in which the noodles are topped with minced meat and ya cai, a famous vegetable preserve whose dark crinkly leaves add salt and savour. Every restaurant serving traditional Sichuanese food has Dan Dan noodles on its menu, and you can now buy Dan Dan noodle sauces in the supermarkets that have sprung up since I first lived in Chengdu. I've lost count of the different versions of the recipe I've tried over the years. Yet in all my wanderings, I have never come across Dan Dan noodles as delicious as those made by Xie Laoban in his modest noodle shop near Sichuan University.

Of course I tried to persuade him to give me his recipe, but he would never divulge it in its entirety: instead, he tantalised me with fragments. On one occasion, he grudgingly let me watch his staff assemble the seasonings in the bowls; another time he let me taste his oils and sauces; finally, he told me me the ingredients of his niu rou shao zi, the marvellous minced-beef topping. Eventually, with a great sense of relief and achievement, I managed to put together the pieces of the puzzle, and to reproduce his recipe at home.

It was like that until my final visit to his shop, sometime in 2001. This was during the architectural reign of terror of city mayor Li Chuncheng (or Li Chaiqiang -- 'Demolition Li' -- as he was popularly known). Li was a man determined to make his mark on the era by demolishing the old city in its entirety, and replacing it with a modern grid of wide roads lined with concrete high-rises. Great swathes of Chengdu were cleared under his command, not only the more ramshackle dwellings, but opera theatres and grand courtyard houses, famous restaurants and teahouses, and whole avenues of wutong trees. Chengdu hadn't known such ruin and destruction since the Cultural Revolution, when Red Guards dynamited Chengdu's own 'Forbidden City', a complex of courtyards and buildings dating back to the Ming Dynasty (a statue of a waving Mao Zedong now stands in its place).

For years afterwards, whenever my Sichuan University classmates and I returned to Chengdu from Paris, London, Munich, Verona or Krakow, we would go to Xie Laoban's for a nostalgic bowl of Dan Dan noodles. And whatever ends of the earth we had come from, and however many hundreds or even thousands of bowls of noodles we had eaten in his shop in the past, he would look at us without a smile or the merest flicker of recognition, and simply ask in the same deadpan Sichuan dialect, 'Sa zi mian?' If we were lucky, he might give us a perfunctory nod as we left, bidding him goodbye for another year or so. It became a bittersweet joke among us, this refusal to acknowledge who we were.

The lanes around Xie Laoban's noodle shop lay in ruins, bony cadavers of wood and bamboo, and his restaurant clung to one or two other little shops in a precarious island amongst them. When I wandered up for a lunchtime bowl of noodles, Xie Laoban gave me a sunny look and, to my amazement, almost smiled. And as he took orders, settled bills and chatted with his regulars, he seemed mellower and less spiky in his movements. By his own standards, he was radiant with bonhomie. What was behind this miraculous transformation? Had he fallen in love, or won a fortune at Mah Jong? Or had the obliteration of the city, and the impending destruction of his business, just filled him with a sense of the lightness of being? I shall never know. I sat there and ate my noodles, which were as fabulous as ever, and then it was time to go. I never saw Xie Laoban again. Later that year, I went to look for him. I wanted to tell him that I had described him and his shop in my Sichuanese cookery book, and published his recipe for Dan Dan noodles, which was now being read and perhaps cooked by a network of Sichuanese food fans all over the world. But the place where his noodle shop had stood was a moonscape of debris, a great plain of rubble, scattered here and there with shattered pickle jars and ricebowls. And none of the passers-by knew where I could find him.

Of course, in my first year in Chengdu, the idea of writing a Sichuanese cookery book hadn't even occurred to me. And it would have been hard, then, to believe that such a vibrant old city would disappear in just a few short years. I passed my time there in pleasure and idleness. One day I might spend hours in a teahouse, memorising Chinese characters; on another I might decide to visit a nearby fishing village to see what people there were cooking for lunch. Some friends and I began taking Qi Gong lessons from a retired Chinese doctor in the shady gardens of the Qing Yang Gong Taoist Temple, where we learned to sense and control the energy flowing around our bodies. The Russians, Sasha and Pasha, persuaded one of the illegal cinemas to hold a special screening of Pulp Fiction (a bootleg copy), which turned into a riotous party. With my German friend Volker and eight other foreign students I hired a bus for a wild trip to eastern Tibet. But on many days, I simply meandered around the old streets of Chengdu on my bicycle, waiting for something to happen. And it usually did.

In one of my favourite teahouses, I befriended an ear-cleaner called Xiao Chang'an. I was familiar with the sound of him before we ever met. I liked to lie back in my bamboo chair, eyes closed, a bowl of jasmine tea by my side, listening out for the street vendors as they passed. A sharp, metallic twang heralded the arrival of the ear-cleaner, his shirt pocket filled with a terrifying array of instruments: little knives, copper spikes and tiny scoops, and a few delicate goose-feather brushes. Xiao Chang'an was a regular in this particular teahouse, and I had often watched him poking his instruments into the ears of teahouse customers, who lounged in their chairs with expressions of extreme bliss on their faces. One day we struck up a conversation, and he told me about his trade. He explained about the acupressure points that he stimulated with his little prongs and knives, and told me that the art of ear-cleaning dated back to the Song Dynasty. 'These days,' he said, 'some women use ear-cleaning as a cover for prostitution. They may carry the right tools, but they have no idea how to pleasure an ear.' I was intrigued by everything he told me, but much too scared to let him give me a practical demonstration of his art.

One sunny afternoon, however, after I'd known him for a while, my resistance crumbled. I settled back nervously in my chair and let him have his way with me. He began by gently drawing back my hair, and stroking the skin around my ear with a small blunt knife, sending shivers of pleasure all over my body. Silent and concentrated, he then began to scrape and probe inside my ear with his little scoops and copper prongs, and to twirl around a series of feather brushes. The most thrilling sensations came when he placed a brush in my ear and then touched its handle several times with his humming tuning fork. The vibrations sent a rhythmic sound like the buzz of a grasshopper into the depths of my ear.

Life in Chengdu often seemed surreal. The most extraordinary things happened on a daily basis. It was impossible for any of us foreign students to have a 'normal' life there, anyway. Whatever we did was inherently eccentric and fascinating in the eyes of the locals. We were recruited to appear in advertisements and films; images of our faces were printed on packets of soap. I spent a day at a theme park, dressed up in a Spanish flamenco costume and full stage make-up, chosen for a role in a commercial on account, said the director, of my 'mysterious eyes'. If we had striven to go about our lives in a discreet and boring manner, we would still have drawn crowds and gasps of amazement wherever we went. In practice, this gave us licence to do just about anything.

One night, I took a taxi with my Italian friends Francesca and Katya to a dinner party in another part of town. We hadn't gone far when the taxi broke down in the middle of a vast open junction (there were few private cars then, and no traffic lights, so vehicles just wove their way across these massive intersections in an ad hoc manner). Our driver got out to tinker with the engine. We were in a stupid, drunken mood, giddy with hilarity, so we shoved a rock cassette into the car stereo, turned the volume up to the maximum, stepped out into the road and began to dance. Our driver smiled at us indulgently, as people tended to do. Soon another taxi ground to a halt beside us, and its driver leapt out to gawp at the spectacle of three laughing foreign girls dancing in the middle of the road. It was followed by another, and another, until the whole space was gridlocked with a crazy zigzag of abandoned taxis, twenty or thirty of them. At that point our driver got the engine running again, so we jumped back in, wove our way out of the chaos of parked cars and zoomed off, looking back at a sea of astonished faces.

I remember one hair-raising lunchtime when Zhang Changyu, a kindly scholar of culinary history whom I had met through my Chinese teacher, invited me out for hotpot, and ordered a whole dishful of expensive pig's brains, just for me. He scooped them up in a little wire sieve, which he dipped into the simmering broth. And then he turned the brains into my seasoning bowl, where they sank gently into the sesame oil and chopped garlic. At first I tried to hide them under the garlic, and to flip them on to the waste plate with the fishbones, distracting him with lively conversation. But it just didn't work. Every time I 'lost' some brains by my feeble subterfuge, he would tip some more into my bowl. In the end, I just ate them, with a sense of grim resignation. They were as soft as custard, and dangerously rich.

In such a bizarre context, it wasn't surprising that my own tastes were becoming ever more adventurous. At first, like most foreigners, I steered away from the wilder waters of Chinese cuisine. Dining out with my classmates, I would order chicken or pork rather than frog or loach, and always choose flesh over offal. But as I made more Chinese friends, it became impossible to continue with such fastidiousness, if only because of my English good manners. Some well-meaning Chinese person was always plopping a bit of pig's intestine or cartilage into my ricebowl, as a special favour.

Sometimes my reticence over a particular food was overcome through simple drunkenness. The Chengdu equivalent of the late-night döner kebab in 1994 was fried rabbit-heads, a snack I'd heard about from a Canadian friend. I'd seen the rabbit-heads sitting ominously in glass cabinets, earless and skinless, staring out with beady rabbit eyes and pointy teeth. The idea of eating one was utterly revolting. But one night, after a long dancing session, I fetched up at a street stall bedraggled and hungry. My reason befuddled by alcohol, I ate my first rabbit-head, cleft in half and tossed in a wok with chilli and spring onion. I won't begin to describe the silky richness of the flesh along the jaw, the melting softness of the eyeball, the luxuriant smoothness of the brain. Suffice it to say that from that day on I ate stir-fried rabbit-heads almost every Saturday night. (Later I learned that a Sichuanese slang term for snogging is chi tu lao kenr -- eating rabbit-heads.)

Affection, too, played a part in my growing omnivorousness. Affection for my Chinese friends, who would offer me wobbly morsels of dubious-looking food with expressions of such eager and expectant kindness that I couldn't refuse. And a growing love also for Chengdu, for Sichuan, and for China. Sometimes the most disgusting things can taste delicious when they are associated with a familiar and beloved place. Aside from the offal and the weird delicacies, certain unlikely snacks became part of my Chinese gastronomic landscape. Huo tui chang, pale pink 'sausages' made from an unspeakable mix of reconstituted pork and cereal squirted into a red plastic sheath, were sold on every railway platform in China. Eating them became part of the ritual of long train journeys. They still make me nostalgic and I can't resist buying them occasionally, even though nothing would induce me to eat that kind of thing in England. I also became addicted to ta ta bubblegum, which was sold as a long, spiralling pink ribbon in a flat round box: this is probably why, having had perfect teeth until the age of twenty-five, I went home to England after my time in Sichuan and had to have seven fillings.