HO CHI MINH CITY — The night begins with a concerto of motor bike horns as the heat lies like a damp rag over everything. All the mopeds take off at the light, tooting their horns at once, and in the twilight we leave behind Ho Chi Minh City's tourist district, with its French-colonial buildings, town hall and theater. We plunge instead into the nightly bustle of the city formerly known as Saigon.

Nguyen Tien is a confident driver and tour guide. "We're going through Chinatown right now," she says in perfect English front the front of the moped. No sooner has she uttered these words, we smell the medical, slightly musty herbs and roots of traditional medicine. The camera in the driver's helmet is capturing the scenes around us. Too bad it can't capture scents too. Like the other smells on this "Foodie Tour" of Ho Chi Minh City, these are to be savored.

Of course, Ho Chi Minh City has a rich nightlife, where gourmet restaurants, styled establishments and airy "sky bars" that present the Vietnamese metropolis from a bird's eye view abound. But anybody out with Nguyen is treated to another city perspective entirely: from the ground up, outside the comfortable air-conditioned interiors and straight into the chaos of the night markets via moped.

Photo: Sam Sherratt

Moped guides such as Nguyen come to the hotel door, and are easily recognizable in their long white outfit of pants with a tight-fitting, side-slit tunic, and their little candy-colored mopeds. After sundown, Saigoners meet in thousands of cookshops and open-air locales. But first, we need to make the obligatory round through the district. Particularly on Fridays and Saturdays because, since the 1990s, this is when there are aimless show races between two-wheelers with zigzag maneuvers and constant horn blowing.

Hours of dining begin

Now, along with a hundred other Honda drivers, Nguyen drives straight into the crossing. Miraculously, a route opens, and we reach the Dong Ba soup kitchen in the first district. It specializes in only one dish: Bun Bo Hue, from the imperial city Hue in the country's center. In the steaming soup bowl are long noodles, strips of beef and onions. Using chop sticks, we mix it with soy bean sprouts, strips of banana flower and a spinach-like green called morning glory, along with a bit of chili or fish sauce.

Photo: Charles Haynes

While the guests slurp the delight, another guide, Tai Dang, talks about Vietnamese cuisine, showing mouth-watering dishes on his iPad. He uses the opportunity to introduce some of the more gruesome specialties, at one point showing a cute little dog. His audience is outraged. Tai himself doesn't like dog meat, and says he'll leave that to his northern countrymen. He only tried it once, at a client's request.

"Di thoi, let's go!" After eating, everybody gets back on their mopeds, and soon we're off to the Bui Vien in the backpacker quarter, then past the kebab shops, massage parlors and tattoo studios and back to Chinatown, the fifth and oldest district in Ho Chi Minh City. After a photo op at the Binh Tay Market, the city's wholesale market, Tai Dang tells the story of Cho Lon, which means "great market." For 300 years, the Chinese and their descendents who fled from southern China have been trading here legally and illegally on the surrounding streets and sidewalks. These days, the smartphone has replaced the abacus, and the sweet smell of opium no longer wafts through the area.

Shopping while on mopeds

When the Vietnamese go food shopping, only seldom do they dismount from their mopeds. Take the night market, for example. Customers maneuver through the narrow streets between the stalls full of baskets laden with fruit, vegetables, hens and hatchlings. Fish and crabs are stacked in plastic containers. The "luck birds" twitter in their cages, and the voices of market women hawking their wares rise above the din of the mopeds.

Photo: Robert Lafond

In district eight too, visitors are welcomed with delicious smells: pepper, chili and other nose-tinglers. In Trung Son, there are barbeque and hot pot, or stew, places all over, all of them with 300 seating spaces under corrugated roofs. At the "Lau de 3 Q," the dish of choice is goat meat with okra shoots, cooked on the table's coal grill. To accompany it, diners dunk mint and basil leaves in a dip of salt, pepper, chili paste and lemon or soy sauce. After that come grilled prawns and squid on skewers with icy glasses of "Saigon Bia," or beer.

Twenty minutes later, we're in Phu My Hung, a clinically clean and chic part of the city with town houses and 20-story apartment blocks with tennis courts and Olympic-size pools next to parkland with jogging paths and artificial lakes. Two million people live here. "Fifteen years ago it was a swamp," Tai says. The streets are deserted. There are no mopeds, and hardly any cars or people. Street lights change in the emptiness. It's like a ghost town.

Those who participate in the tour shouldn't let their plates be piled too high, just try a little bit of everything the way the Vietnamese do. Because the last foodie stop, in the fourth district, when you are practically too full to eat another thing, surprises you with the best the tour has to offer.

It's on an inconspicuous, somber little street. A pair of red stools sit before a white-tiled house facade pushed against a long table, right next to the parking space for motorbikes. Servers bring plastic chairs, plastic dishes and napkins. Then they bring the food: quail and mountains of crab claws in chili and garlic. They also bring scallops garnished with spring onions and finely chopped peanuts. Five of these cost just two euros.

Photo: Cristina Bejarano

After this treat, Tai recommends duck eggs with the embryo ("lots of protein, good for men"). But he only eats one before getting back on his two-wheeler and rolling through the night to the hotel merrily blowing his horn.